What I like about RC4:
arena upgrade
wingman can get armor repairs
Great upgrade to St. Kat's and Heretic systems
icons for damage types
more fun to play through
new weapon enhancers
great new weapons
Heretic system reminiscent of Freespace 2 (one of my faves) final level
What I like less

turn speed reduction when ship is weighed down
AI ships docking to wreckage and stealing my spoils of victory before I get there is frustrating
It's very easy to accidentally hit friendly ships
shooting from edge of planet/moon makes it too easy to destroy some enemy bases
shockwave from enemy base destruction is too powerful and keeps killing my wingmen
autons are helpful in the beginning but even the best autons suck in later systems
too many auton dealers
too many clavius insurance conglomerates
wingmen can't come close to handling themselves in later star systems
limited duration of blue/green etherium crystals
blue etherium crystals are too rare sometimes (only found 2 in playthrough 1 and 2. But I found 10 in 3rd playthough)
Using blue/green etherium crystal permanently wipes out other enhancements -- can this be made temporary?
too much screen flashing when armor is taking damage
unidentified devices
Sung Citadels seemingly IMPOSSIBLE to take on without particle resistant armor
ventari - VERY DIFFICULT to destroy their base & ventari destroyer without taking equipment damage
iocrym veil should protect more against particle and ion damage
rasiermesser research lab station can't defend itself against most threats
Things I would like to see:
1. widescreen support
2. ability to customize your wingman's ship
3. option to remap keys, or switch to different key configurations. My right hand is cramping.
4. quantity of item already in cargo hold when purchasing or looting
5. ability to match speed/heading of target ship (form up on their wing -- i.e. for escort missions)
6. option to pay someone to identify unknown items in your cargo hold
7. tinkers in later star systems
8. how many rin I have in the ship screen
9. option to order wingman to protect a target
Thanks for the great game