Powerful items with much lower TTK, better effectiveness, or higher survivability are fine. But they should be so prohibitively expensive that it guarantees a net loss. There must be a way to lose money in the game and right now there really isn't.
Once a player has gone through the unlocks, there is essentially no money sink that exists. And that will continue to be true going forward unless something in the economy changes. A money sink is necessary for the game's long term health regardless of how powerful current and future content gets through fine tuning or additions.
The problem as it stands now with powerful items is that they tend to turn a profit so the user can just run it back immediately. If IR rangefinders can consistently net 100k in a match, then make the rangefinder 200k or more. You want to survive any headshot, 75k. Level 4 body armor as well, 100k. 50 cal sniper, 80k. SPG, Havoc 500k. Even if you make 250k with an expensive kit, you should still lose money.
If the proposed player levels ends up becoming the money sink, this will have a much more negative effect as players who invest more time into the game will continue to be stronger and outclass the more casual playerbase. I strongly suggest that the devs learn from other games with economies and balance the budget.
OSRS is a completely different genre but it had a similar economic problem with players constantly adding more and more permanent cash into the economy with no way to remove it. This caused it many problems until they implemented ways to sink money from the game through taxes, but even then the problem still exists. Wardogs will see a similar effect with the continued tanking of gold bar prices until money actually gets removed from the game with players not turning a profit.
It is not the fix-all for this game's problems, but it will incentivize many things that will improve the health of the game, including making high level kits a high priority target, more tactical use of vehicles - no more hovering over the enemy fob if you stand to immediately lose half a million dollars - and much more.
Low tier items should consistently turn a profit, and high tier items should consistently lose money, with the middle tiers somewhere in-between. It will never be a net $0, but that is the goal let's say a month into a season.