MWO has completely replaced WoT for me. It is ridiculous how long it takes to get a high level tank in WoT, whereas, in MWO, you can run the fattest Mech in under 50 matches, because there is no dependency tree. This works, because mechs never become redundant, even the cheapest mech has its role on the battlefield, not only as a scout, but as a fast skirmisher. The reason for this is because weapons do a lot less damage than in WoT. I don't think there is any loadout that can one-hit even the weakest mech in the game consistently. Also, there is no tiering, so you can play with your tiny 20 ton mech against a hulking 100 ton monster. Actually, there is tiering, but it is based on player win/loss ratio, not on the mech he's running.
There are so many more things that are better than in WoT, e.g. mech customization, weapon variation, the actual gameplay, maps, I could go on forever. Also, it has battlemechs instead of tanks, probably the only reason a sane man needs to immediately jump the boat.
The only bad thing about MWO is that development progresses sooooooooooo slowly. But what's there is great.
