This is a fun game that does not require you to spend money to progress.  With that said, progress does stall out (at least for a player like me which I believe is most players, if not a little more active than most).  The developers are doing a good job of making it tempting to spend some money on the game but their prices and rewards are not worth it to me and seem to lack the overall draw (reasons explained below).  The slow progress for upgrading, purchasing new, higher ranked weapons and bots can be frustrating, but the DEV's need $$$ too.  I feel the rewards for A-Coins specifically are lackluster, but doable for those who do not regularly get in the top three in tournaments.  The AI can be challenging , but who wants to play a game where the AI just lets you freely blow them up?  

The "Pay To Win" players and the Shop:  This is what I find to be the shortcomings of this game.  It is fairly difficult to save up 10k A-coins (for me it is at least)  and the shop's values for A-Coins is garbage in my opinion.  $10 for 1200 A-Coins is what I think the rate is right now.  1200 A-coins doesn't even get you enough to upgrade long arm 8's to 4 stars....WHY WOULD ANYONE PAY $10 for such a crappy, mid tier upgrade?  There have been some offers like the keys deal where you got somewhere around 50 keys and 4k A-Coins for a decent price (I think it was less than $10.  Deals like that are the way to go if you plan on spending money in this game, but they are few and far between.  

The game modes:  The game modes are fun and serve their purpose, but lets be honest, if you are playing anthing other than tourney all day long, you aren't playing to get rewards and upgrade your mechs.  Or you have a challenge to complete for the small A-Coin reward.  Give us more opportunities to get some more value from things like CPC.  Again, the only game mode with purpose is tourney.  

Maxed out/ upgrade rewards:  Again, there is almost no value in upgrading your mechs.  Aside from HP and energy levles for weapons, NOTHING CHANGES!  The only Mech's that benefit from being upgraded are those which deal damage with their abilities, Killshot, Redox, and Surge and maybe the Juggernaut and Ares shildes (not sure about hem at this point).  This could be changed in many different ways.  Something like reducing the reload times, increasing Mech speed, or.....THE MOST LOGICAL SOLUTION.....MAKE THE MAECH ABILITIES UPGRADE WITH THE MECH.  This could be as simple as increasing the range of some specials like gaurdian or zeph, increase the amount of time the ability is in play (stasis barrier, stealth mode) or even allow the Lancer to jump a little higher....Hmm I wonder why Killshot is the META?! but not really).  

So in short, boost mech abilities for upgrading them, get rid of the duplicate 5 star mechs and allow faster reload times when they get to 5 stars (maybe too OP and unbalanced if that happened though) and give better rewards or more rewards fot game modes other than tourney.  Then again, this is coming from a mid tier player who struggles with waiting a month or more just to unlock carbines.  Good luck everyone, see you in the arena.