There could be two ways to download mods.
One based on the current "log-in via the game and the mods download".
The other a separate page where mods could be downloaded without using the game. I assume the best way would be a Multiverse page. This could either be freely available or require logging in, there are advantages and disadvantages to both these options.
When only registered mods could be uploaded to the Multiverse, logging in was a good idea. Now that many unregistered mods will be uploaded there could be a freely available section and a logged-in section.
When using the web I find the need to login/register/passwords/all that fiddling around to be a big disincentive. It frequently causes me to close the page and never return. A lot of this is due to the fact that many sites don't have a really easy to use registration process, mostly it is tacked on as a not very important part of the site. The potential user has to decipher how to do it, so quickly loses interest. Possibly a freely available section could offer a few of the better mods to act as an 'interest generator' to convince people it is worthwhile to take the time to register to get access to more mods.
Possibly need to cater for two different levels of interest.
One level would be a player who just wants to download and play mods. This suits the game login system. Nearly everything would be automated. If a mod can be played then it is available and downloads automatically, including upgrades. If a mod won't work in that game version then either the mod isn't displayed or is disabled with an explanation of why and info on how to make it available. The player doesn't want to mess around with folders, compatibility, command line options etc. Basically they don't want any problems stopping them from playing.
A point from community members about breaking save games with auto updates is one point that needs to be considered here. Either somehow stop this from happening or offer an explanation about why. Others will have more coherent opinions on this.
The other level of interest is someone who is happy to sort things out for themselves. Checking and updating game versions, mod compatibility, updating mod versions, etc would all be handled by the player. What is needed is a friendly UI where info can be checked and mods downloaded as required by the player.
A prominent difference between adventures and extensions. Possibly a separate page. And an explanation of how they differ. When I purchased CC and EP I didn't really have any idea that one was an add-on to SOTP and the other a completely separate adventure. I think a lot of this confusion comes from most people thinking SOTP and Transcendence are the same thing (I did), not realizing that SOTP is only one of unlimited adventures that can be played using Transcendence.
One of the disadvantages of xelerus is that a mod is a mod. The player doesn't really get much info for distinguishing different types of mods. And looking at the current descriptions of EP and CC there isn't really an indication of how an adventure differs from an add-on mod although the (new?) player info page is great.
An option to see all add-on mods for an adventure might be useful but only add-on mods that work for that adventure. If the player downloads a mod thinking of using it in EP and it doesn't work in EP then the player's time has been wasted. Never a good thing.
The pages could be laid out in a way that could be used to generate interest in the paid expansions. The SOTP adventure could be enabled (because the player already has it) and linked to CC. The CC option could be disabled with a comment saying it is a paid expansion. Under the disabled CC option there could be a list of CC-dependent mods, eg auton mods, that are disabled and only become available to players who have purchased CC. There wouldn't be any point in having the mods if the player didn't have CC anyway but the "Buy this, get these free" and "Unless you buy CC you're missing out on these mods as well" mechanisms do increase interest.
Similar to Trans and TransNext, a prominent difference between stable mods and beta mods. In theory I suppose beta mods shouldn't be uploaded but the advantages are worth it IMO. More player enjoyment because the mods are available earlier and more feedback for developers because of a larger 'audience'. It would be good to explain that the mods are in development so there is a chance of bugs and crashes.
A clear explanation of the purpose of the mod. The description should cover most of this but clearly shown categories would be a great idea. This lets the player have a good idea where to look for whatever type of mod they are interested in. Fancy effects, playerships, more systems, lots of combat, trading enhancements, custom weapons, godmods or modding mods, etc. I don't feel that the categories on xelerus are a good example but I haven't put any thought into what would be good categories either. Others will have good ideas.
The ability to download the source folder in a zip would be good. This would be a great start for new modders. And the option to download any tdb mod as a zipped folder of xml files by selecting "Download xml version" or similar could be helpful. Using Transdata isn't too difficult but it is something else that needs to be learnt initially. The learning curve for new modders is already steep enough without having to use command line code as well.
Version information. Enough info should be available so a player very rarely sees "Requires a newer version of Transcendence". If this shows then downloading the mod was a waste of their time. Possibly the mod could be disabled from downloading if the player is using a game version lower than the mod requires.
One of the best features of xelerus is the search display. A search of mods by one of the categories, last updated, rating, etc, shows a list of over 30 mods. The rating, author, version, downloads and uploaded/updated date show for each entry. This is excellent. Lots of info all on the one page without any further input. Nothing is more annoying than having to hit a "see next 5 entries button" dozens of times, especially if it refreshes a webpage, and then it's even worse if you have to click on every entry to get more information. Aarrgh! (The "add 100 entries" feature on the Ministry is excellent, well done.)
As a modder I use xelerus to upload mods because there isn't a delete option for Multiverse Mod Collections yet. The collection would soon grow to be unmanageable. The download disable feature is a great addition and I've already used it. Thanks. In the short term, it would be good if the disable feature was remembered between log-ins. Currently a download can start before you can get to the page to disable it.
The ability to download mods directly from the Multiverse is, for me as a modder, the desired option. So clicking on a mod and having it download directly to my computer.
This would be for new mods that I want to look at. So again I want to know what the mod does, when it was released, what game version it uses and any other mods that it needs to run.
I would also do this if a mod had been updated. The infomation needed would include the upload date, if the required game version has changed and what mod content has changed.
Not the most ordered of thoughts. Just notes scribbled down as they occurred to me.