First, debt never NEVER causes you to lose anything. At worst, it slows your leveling speed until it's paid off. However, since release they've increased the amount XP you earn (especially by completing missions and story arcs), cut the amount of debt you get from a death in a mission to half, and recently cut the debt cap in half. Debt is now a minor inconvenience, certainly no worse than having to travel back to your corpse. In missions, you can easily erase 2 or 3 deaths worth of debt by the end of that mission.
Second, stop holding up Guild Wars as an example of a 'free' mmo. Guild Wars is no more of an MMO than Diablo 2 is. It's a multiplayer game with a fancier avatar chat lobby, that's all. Not to slander the game, it's fine for what it is, but labeling it as an MMO is a pure marketting ploy.
And finally, CoV brings a lot of content to both games. Open PvP zones with different types of gameplay, superbases, gladiators, crafting, loot...many of the things people so often complain about CoH lacking are now in there. All of that on top of the villian game, the new classes, new powersets, and all the story and missions exclusive to villians.
Yes it can get repetitive, as can all MMOs, RTSs, FPSs, and pretty much most games out there. But that's why we have more than one game.