Some of you may remember me posting here some years ago, most probably won't. But I had been playing Infiltration during its first days as well as during some of it's latest version days. The reasons I stopped playing it was simply that it didn't manage to fully accomplish "the infiltration dream" - modeling fully realistic combat. For all these years I've always been hoping infiltration will actually live on - either as a new mod or even as a new game some company would actually decide to go ahead and make - and make properly. I'm quite sad this hadn't happened yet.
If infiltration 3.0 would ever actually come to being on any engine whatsoever, what I would really expect from it would be first and foremost realistic mechanics. Game types and playability can always be developed, modified and balanced later on.
The most important idea of infiltration to me is the actual simulation of a soldier. From holding a weapon and aiming down its sights (or not aiming and still trying to shoot...), to running around in full combat gear, and taking realistic damage from shots. Being an ex-combat soldier and sniper, the recoil effects in infiltration should be totally redone, basing it on personal experience of people, basic physical laws and data on the weapons. Ballistics are also a critical part of realism to me - especially for longer ranges. Terminal ballistics should also have some kind of modeling based on whatever data can be found on experiments that were done with different weapons - while this part would never reach full realism it can be greatly improved. Things like "velocity breakpoint" for fragmenting 5.56 ammo, loss of velocity over distance and critical vs superficial wounds are very important.
At the end what I want to see is an infiltration "core" that will actually simulate everything properly, so I can go in some random map with another person and we could shoot eachother and have it feel like we were shooting eachother in real life. If done well enough, you could actually feel the differences of different loadouts (weapons, protection, ammo) would have on your performance in combat, and have a strong relation to how such a loadout would work in real life - unlike other games where loadouts are simply "balanced" so no certain one is overpowered.
When it comes to loadout choices - I believe if anything is widely used enough so that enough information about it is available to model it properly - it should be in game and equippable. I don't want your grandma's home-made self-designed handgun in the game, but anything that is actually used enough over the world so that enough information is available for realistic modeling has its place in infiltration in my opinion.
Once you actually have a properly working "core" and some well-designed (read: realistic) maps are made, setting up anything between the most simple dtas to the most complicated objective-oriented game is just a matter of some balance work. But let's face the facts - since both sides will have humans in it that will want to see combat, any kind of game objective is really no more than simply encouraging combat and discouraging camping. The most basic can be seen in america's army - attack the objective or run out of time and lose. Anything beyond that (more objectives, reinforcements, more/less time) is just a matter of balance.
What really matters is the "core" though - having a realistic combat system that will be the basis for all of this. As without realism, no matter what kind of maps and/or game types you have, it just won't live up to "the infiltration dream".
As for myself, I've been playing world of warcraft for 3 years now, and possibly finally quitting it. After finishing the military service 1.5 years ago I went to study physics and computers in university (during my 2nd year now), so who knows, maybe I'll actually have some knoledge in the future to help more than just throwing ideas around and tossing some bits of military experience.