I think what could help to make the game better is to keep the four abilities limit, but make particles independent of your deck and spread over the map, possibly in various sizes and colours to denote points, that you only need to step into to pick up.
No, balancing your options against your resources is an important part of deck-building in basically every TCG out there, and it's no less important here. There are arsenals that are quite successful and are designed to rely on minimized aura (as well as the opposite).
It should be noted that there are specifically skills out there to counter high aura and high level, as well as sap aura from opponents. How many aura particles are in your arsenal is a thing that you take into consideration as a strength and a weakness for more than simply your relative chances of getting them.
I also think including roll and climb would help to make the game a bit more dynamic as it affords players more options or closing distances so it's not just dudes hurling shit from a distance at each other.
Hey, guess what you can build an arsenal around.
Including too much mobility would trivialize the range and tracking aspects of a lot of skills - which is something that necessarily has to remain in a precarious balance for basically the entire game to work. Dashing, jumping, and buffing your movement speed (both permanently and temporarily) are things you can very much build an arsenal around. It wouldn't do well for the rest of the game if just everyone always had these options.
It's very important to realize how much depth this game has. Like any good trading card game, balancing your arsenal around a strategic paradigm - both in available resources as well as things you can actually do - are paramount to the game having any reasonable amount of depth. At the same time, what Phantom Dust is designed around and delivers on, is the fact that when it comes to actually playing the game, it's in 3D and in real-time - and every skill in the entire game takes this into account (some more than others). You have all of these options, and every single one of them is tightly bound to every single other option with regards to how feasible it is and needs to be. That's the core sign of a well-designed game.
Taking power away from decks and placing them directly into passive power that the player has innately is almost never a good idea, especially when building and using your deck
is the game.
The only thing really stopping you from making high-speed CQC arsenal is what skills you've acquired, which is just a function of time, really. And I guess anyone with an arsenal designed to counter it - but that's going to be a constant (as it is in any TCG).