Another important aspect that I hope they adopt from TF2 is that even if you use default items (e.g. weapons) you will not be in disadvantage when playing with users that spent money on items.
I'm assuming that you won't be able to buy things in the marketplace and bring them into other people's games. With mods in the previous UTs it's been very much that every player in a game is on exactly the same footing except for player skill.
You start with the same gear, and anything else you can get is sitting around the level to be picked up by everybody.
I'm not sure how the community would feel about that. UT puts you in situations where your opponent is carrying around 10 different guns at once, and the split second "he just pulled out a sniper rifle" reaction can be pretty important.
If they do have weapon skins carry into the game, Epic will have to be gatekeeper on approving all of them. If not, you'd have people reskinning their rocket launcher to look like it's something else, with negative gameplay effects.
Perhaps we'll see two tiers of aesthetic mods? Ones that anybody can create and use in their local / self-hosted games, and others that have been approved for online play?
You start with the same gear, and anything else you can get is sitting around the level to be picked up by everybody.