Engine, I think if you give it a try you will be happy. I was worried myself, being a huge fan of Fallout 1 and 2. Tactics, not so much ugh!
They stayed very true to the universe and I'm having trouble understanding peoples complaints that you listed.
The ghouls are still ghouls. Maybe slightly more zombie looking but I'd attribute that to simply better graphical representation. They still communicate and act like the ghouls from the previous games. They did add in "feral" ghouls, but in all honesty they fit and make good sense in the story.
The super mutants are just like they used to be. Created from human experiments to create super-soldiers. They run around terrorizing the humans. You may find a couple friendly ones, I found one wandering around the wasteland besides Fawkes that was a friendly supermutant.
The gear is well done and the engine is different, but such a good transition from all turn based to fps that I was immediately entranced by the game.
I highly recommend it. I've finished the main story with one character and now plan on turning it up to very hard and seeing how long I can last as a melee character. The hand to hand was easy once I picked up a powerfist.