Support! It makes perfect sense for skills to be true-max at 120. I'm going to 120 all skills currently, and it seems like the perfect next step in the game. The reasons for me saying it makes perfect sense are:
1) Master Quest and Completionist Capes are the continuations of the basic Quest Cape. Where is the continuation of the basic Max Cape? The only upper skilling required is 120 Slayer, Dungeoneering, and Invention, plus for trimmed strange and golden rocks.
2) We need more content! Currently, the only things we've really seen released are more locations (Menaphos was an excellent release if you're mid-level, but I myself landed there and after completing reqs for Comp, I may never find myself there again), cosmetics, and pets. I'm not complaining about these new additions, quite the contrary- I'm always thankful for something more to do in the game.
3) If true-max is raised to 120, it gives more room to grow in the game. Potentially, all skill's virtual levels could be raised to 150 to echo invention, and perhaps the XP cap per skill could be raised to 500m. I understand it will make some people angry, but honestly, those I've heard complaining about this idea seem to be the people who are content to be finished with their current gameplay. I would assume Jagex wants to involve people who want to continue playing instead of calling it quits at Completionist.
The game needs to grow. We need to grow. Not everyone will agree, but, hopefully, some J-Mods will!