the game has changed a fair bit since then, Rebecca is now the creative director for Warframe while Steve is off on some quest to make a souls-like. But for now the future seems bright. Grinding is well uh, i wouldn't say it's easier but its also not harder, just different and a little more forgiving. you probably just missed the open world map and faction on Venus and Deimos, and a LOT of story quest.

If you are interested in 1999 (is breddy good) you will HAVE to do the following quests The Second Dream, The War Within, The Sacrifice and my favorite The New War, which is by far the longest one with the most content, it's also really cool and diverges a bit from the standard run'n'gun-kill-everything-ever nukeframe gameplay, offering much more story content in exchange for a different, slightly slower gameplay.

post-TNW you will unlock a whole lotta content, like Kahl of Duty missions (also my favorites, but a lot of people hated them and now they're abandoned), Archon hunts (which give you archon crystals that soup-up your chosen frame of war) and a whole river of Quests that you have to go through to play 1999 like The Kalymos Sequence and Angels of The Zariman, each one opens up their own syndicate and tile-set to play through.

Overall, you have a lot of game to eat through, but i personally wouldn't rush to the finish line too fast cause end game is boring.

take your time, enjoy the game and cruise at your own speed.