I played Warframe when the game was released (quite a few years ago). And to be honest the game was cack. It had an interesting idea for a video game. But the gameplay and progression was mediocre (hence the 60-70 metacritic score).
I just gave the game another try last week. And it's probably now one of the best multiplayer games I've played on the PC in a long time. It's a completely different game. The changes to the game are actually mind blowing. In terms of progression/mission content and especially gameplay, it is leagues better than it was when the game was first released (when it scored 6 and 7s). It's clear the developers are making a game that they want to make (instead of a game to please the casual mainstream), and I recommend everyone give this game a try.