I haven't played the game since late 2014, came back since my friends wanted to try the game out in August after I told them about the Plain of Eidolon announcement.
They jumped the gun on starting to play the game because we don't even know when that content comes, so they aren't all that invested, but I'm way more into the game now than my previous 2 attempts (even between those two tries the game saw big overhauls). Last time I couldn't even dream of getting anything Prime but now I go on the occasional Fissure binge.
The feel of progression in this game is so much better now. The interplanetary Junctions go a pretty good job of pointing the player the mechanics or content they should try and get familiar with.
Didn't expect I'd get so fond of a, in essence, a repetitive loot grind game, but the thing is that I'm spending so much time seeking for interesting sidegrades, and that is so much more rewarding than seeking bigger numbers. I might have the occasional situation of retiring Paris for Paris Prime, but I am not certain whether my next Warframe will feel better than my Nyx, or my next sidearm will feel better than my Corpus-slaying pet weapon Gammacor. But finding that out will be the part of the game experience and the new gear will feel distinctly different.
Btw, fuck the old Mod system that had you combining mods to build up their power.