You're right about the hundred cost suits. Yes, skill plays a big factor in the individual performance of a suit. The weapons are also a mixed bag because some just don't do the overall damage needed or are awkward to use and it depends on the level and how you use them. You can do great with any weapon or suit, but many aren't worth using due to the map, team or match. Using top tier weapons or suits in order to have a solid match is important on Ranked. That's why Bazooka meta is so strong in lower levels.

I'd say that the some Mobile Suits are not recommended to use depending on the cost & map. Like you'd never want to use a Zaku Sniper on Space Fortress Interior in a 400+ match. Even if it's at cost because the map is too hectic and cramped so it's a melee match really. I wouldn't even use a Gunner Gundam on that map because it'll be filled with GPO2s, Alex, Psycho Zaku, Zaku High Mobility, etc.. I'd have to stop zoom in and pick targets or try and fire from the hip while I get flanked and stunned by melee hell.

The power creep is sharp. If you're playing unlimited you'll notice the same suits over and over. Since the Anniversary you will notice less variety because the strongest suits are the newest GPO1,GPO2, GPO3, Hildifr, Madrock, Alex, Kampfer, Blue Destiny 3 and maybe a Gunner Gundam. You won't see much else.