1) Gameplay mechanics and features -- I LOVED everything that was introduced in Ro2. Cover system? Genius. Blindfire? Genius and amazingly executed. Switch to iron sights from scope on sniper by using alt fire? Genius, even loved Ramm's story about how he thought of it. Hold reload to guesstimate magazine? Genius. There are some things though, like voice commands, that could harken a little bit back to the Ro1 tradition. I was totally able to communicate with non-English speakers through the old UT style V based communication system. The wheel in Ro2 didn't have nearly as many applications.
2) Tactical View - Literally genius. I'd like it to be more customizable though. Through some .ini alterations I found on the forums here I had it so that I could hit T and have all the info I needed at my fingertips, but I was in total immersion mode when I let go of the button.
3) Setting -- I'd like a return to the whole Eastern Front. Stalingrad was awesome, but I loved being able to go from Kursk to Berlin to Odessa on the same server.
4) Shooting mechanics -- Red Orchestra does this better than anyone, bar none. I think something between realism and classic would be appropriate. Sway, stamina effects, recoil, snap-to-iron-sights, pivot-while-iron-sighting, etc... I trust TWI can do a great job. I just think a halfway point between the Ro2 fast pace and the Ro1 slow pace would really hit the nail on the head. Zoom more towards the level of Darkest Hour, which felt a little bit more like "focused eyesight" imo.
5) Running mechanics -- Same as shooting, I think meeting halfway between Ro1 and Ro2 would be the sweet spot... it could really appeal to multiple spectrums of the FPS market, satisfying both the WW2 buffs and the newly established lost generation of "I love online FPS but am open to something outside the CoD paradigm."
6) Tanks -- I'm sure TWI will be able to figure this one out. I just hope that they can be integrated back into the game like combined arms maps and Darkest Hour... They're crucial and game changing, but not game breaking. Crawling in the hedges and sticking to the buildings allows one to contribute to the battlefield and dominate the crevices as infantry, but tanks are king in the open field.
7) Squad System -- If the squad system is included, it should be be displayed in a prominent fashion (but also tied into the idea that it won't be intrusive and will fade out once Tactical View is disengaged). Soldiers should be aware of their squad, as much as they are their team. Maybe players would be limited to 3D voip amongst their team -- but able to communicate across the whole battlefield with their squad? Personally, I wasn't a fan of spawn on SL as a fixture. However, I totally respect it's intended contribution to teamwork. I think if it were included, but had a cooldown of every 2 or 3 or 4 minutes or every 3 lives... (We could strike the happy medium between Ro1's suicidal smoke throwing attack leader and Ro2's advance-and-hide spawn point).
7) Suppression -- Very happy it was included in Ro2, but I often found it a little overbearing. I liked that is accumulated in heavy moments in Ro2 so that you felt truly helpless and caught in the firestorm. However, it often led to obnoxious residual and superfluous moments. Like 20 seconds after the firefight, I'm in a room all alone still black and white.... like a posion status effect in final fantasy. I think it should be like Darkest Hour where it snaps your aim off point momentarily, but it also includes an RO2-like status that fades after a couple of seconds. The status should be time based, not meter accumulation based. People would still be suppressed in heavy fire fights, but wouldn't have to cower against sand bags cuz a few shots went off 20 seconds beforehand.
8) Map Design/objectives -- I have a strong perference towards open maps with delineated objectives. The most brilliant moments in RO have always been in a) the open territory one happens to find oneself in contact with an opponent, through coincidence or circumstantial flanking interests or b) the intensity of the defined objective zone... Bridges turned out to be a massively popular Ro2 map, and I think it provided these kinds of moments. There were a lot of Ro1 maps and (especially) DH maps that got this right. The distance ability to advance on foot vs. distance of ability to kill with rifles (and MGs, tanks, etc.) means that a front is naturally established (a concept quintessential to 20th century warfare). Tight maps can be intense and fun... open maps can be tactical and immersive... but it's ideal to smush the the "tight map" concept into objective zones and allow the "open map" concept to flourish in between those particular points of interest.
9) Progression System -- I think the pragmatic route to take is to include a progression system but have it be purely cosmetic... stripes on the sleeve type of thing.
10) Audio -- Ro2 had some amazing sounds, but the mix wasn't balanced overall. Gun shots were recorded in a desert and sounded amazing... but it sounded quiet in comparison to the overall mix. Ro1 had worse actual audio, but it was mixed in a way that made me crap myself when artillery shells were nearby. Source material should be mixed/mastered in a way that causes one to feel immersed in the frontline.
11) 3D voip -- Gotta have it. It would be so so so incredible.