Sorry just got back in the house....
First of all the OP isn't so much about adding Tiers (my bad on the thread title), but about "if" the credit gain for playing an Assault class should be as great as for say a medium. If you add a straight 20 Credits for each damage point inflicted, then hell yeah Assault mechs are going to be Credit making machines.
But lets go back to older MW games. From my recollection unless you had a hard cap on the Lance weight, pretty much everyone spawned an assult mech. There were a few die hards who stuck with lighter mechs, but it was the usually teams of 100 ton mechs slugging it out. The vast majority of Players if left to their own devices will spawn the heaviest mech around and see no point in spawning anything lighter.
Back on the WoT issues, yeah T5 lights against T10 heavies. LOVED those matches, they were usually my highest earners (and I did so without firing a shot and surviving...WoT Vets might be able to explain how you can do this
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). Now MWO is bringing PUG spawns to a battlefield (as well at Lances, but thats another issue). So if players in a majority can freely spawn assaults then you have the following issues.
1. Wait times for Assaults will be the highest
2. Lighter mechs should get a slot easier, but the individual player is at a disadvantage in an 1-1 duel (so will be only popular with a few).
So we have moans about how Assaults have a harder time of it. What WoT did was make it useful to actually spawn lighter tanks (or Tiers), so I ask should a similar mechanic be in MWO to spread the mech population (or can you think of another that would do)? How do you make spawning lighter mechs viable to the player (or shift them away from spawning the heaviest thing they can find).
I'm just thinking back to MW3 and MW4 multiplayer and how it evolved over time (for the determent of the game) on the vast majority of player run servers. I could usually find 10 unlimited weight/no heat servers for every heat/stock only servers. Players usually rail against control, but a lack of control can also make the game less "fun".
And finaly back to WoT, if you joined after the introduction of premium tanks (and the T59 that finally buggered up the game) then yes you will have a poor opinion. But the game in Beta and the in the early days was a lot more fun (a lesson to be learned there as well). I actually stopped at T7 because the matches were actually more fun (for me) than carrying on.