So as far as I have understood, the new Circuit mode enables players to do missions in sequence and get rewards. Among those rewards are warframe parts and blueprints, including frames whose parts or main blueprints are acquired only through their respective quests. While on the one hand I'm glad that new players won't have to endure the grind for parts, I can't help but feel that DE kinda spat in the face of all the players that poured days upon days grinding assassination missions, spy missions, or defection (yuk) missions trying to get all the parts for the warframe they wanted. And it's not like Warframes have MR requirements. The only "requirement" relies on a certain planet being accessible, so you can farm the frame in that planet, but the whole thing is now bypassed with the Circuit mode, and the only limit would be the materials required for building the frames, as they can be exclusive to a planet.
Now maybe I have understood the Circuit mode wrong, and it only enables you to get those warframes if you have already farmed them once or something. But if that is not the case, then what about the frames that are obtainable through quests? Will the quest count as completed once you have made the frame or something?
So in summary, while I have always been a proponent of less grind and more substance, and DE is certainly trying to lessen it, I feel kinda bad that I (and the majority of the playerbase) had to spend so much time grinding, while new players will save a ton of time.