TMNT was my intro to RPGs. Growing up in the U.S. South during the Satanic Panic with conservative parents meant D&D was off the table for my entire childhood. Both TMNT and Marvel I've found the best parts to be the character creation, making your hero with interesting mutations or superpowers. And then both systems sort of fall apart after that minigame - when actual play occurs. I've found this to also be the case for Mutants & Masterminds - with the strange scaling and charts to figure out how fast a Power Ranking 9 Speedster is vs. a Power Ranking 5 Super Alien.At the very first - all of your requirements sounds like you want lethal combat to be a common solution to challenges. For instance the superhero genre is very survivable in general as well as being built around the concept of having interesting options unqiue to each character. You have TMNT & Other Strangeness (not that Palladium fits the other requirements) and MARVEL (FASERIP) on your list of owned games, but they are definitely a minority. But truth be told you have a lot more (high/grim/*) fantasy games on that list as well as some SF versions of that type of play. So are you okay with any genre, or are you looking for a D&D-like in terms that combat to the death is a common occurrence?
With the fantasy games, I think it's a marketing thing. I've seen A LOT more ads and reviews for systems like Mork Borg, Forbidden Lands, Warhammer Fantasy than systems like Blue Rose, Fantasy AGE, Age of Sigmar, (assuming these are more narrative/less grim and gritty type systems). And I think "serious roleplayers" (and critics, reviewers, etc.) speak very highly about products like "Masks of Nyarlahotep" or "The Enemy Within." In the culture, I've been more directed to grim and gritty games. Often, this is counter to what my players actually want to play.
This group specifically wants high adventure, lots of exciting action, killing monsters, etc. They predominantly enjoy a power fantasy (even the adults).
Another genre as a palate cleanser after so much D&D-like fantasy would be fine. But it needs to be a genre that I feel like I have the familiarity to run. (For example, I'd be bad at running RPGs about Wrestling, Anime, Westerns, etc.)
Yeah. I'm thinking that something like a "story loss" to replace a TPK - like what is used in 13th Age - might be a good idea.Or, to flip this around: are you okay with character/party failure as long as it's more like a downbeat in a story, as long as character death is not a common result of that failure?
I've run some lengthy PbtA games. For other groups, I did a Dungeon World campaign and a series of Monster of the Week adventures for a few months. With both systems, I did struggle with "what can I do as the GM?" and "when can I attack?" I did find that both of them got extremely predictable and "easy" - just focus on your "good thing" and you can't fail. Neither system seemed capable of running more than 2-3 sessions before they got too easy and boring.Next question - Good GM tools. A number of systems are a lot lighter on needed (and even wanted) GM prep. For example a lot of PbtA games and other Story Now are forgiving in "encounter building" and adventures are minimal. I see Monster of the Week on your list, and the most recent adventure I saw for that was complete at three non-dense pages. Does looking for "good GM tools" have the assumption that you are looking for a system with a traditional DM style RPG like D&D/PF/etc. where you need those tools? Or would a game that has a lot less reliance on that also fit your needs?
Along those lines, if you could say why Monster of the Week doesn't meet your requirements, that would help clear up understanding for a whole swath of games of a particular style.