Red_Ed

I didn't get it because it has a reputation of being extremely crunchy. So maybe if you like that level of crunch you should probably get it. I hear the world building is pretty good.

but removing the limited number of rolls would backfire

I'm not sure what you meant by that. You as the GM are still in control because you are the one that calls for tests. So you can limit them if you feel they are trying to keep rolling for everything. In my opinion the presentationis different but the game is not that different from other more traditional games.

If you think about it the GM turn is just the regular fantasy adventuring phase with the Player turn being the part where the GM let's the players relax and recuperate, like when they are in a town or making a camp. The only difference is that the game thinks that the adventuring phase should be mostly narration with 4-8 rolls to solve it all and maybe one conflict and that the players phase should be dependent on them roleplaying their characters as they made them in the adventuring phase.

But it might also just not be a good fit for you and your group.

I was also considering a thieves guild game played with Swords of the Serpentine.

I was involved for a short playtest of Stonetop, but wasn't impress with the mechanics of the game. It claims it is a game about your community but, once again, there is no real mechanics for it. Playing as the Judge (?!?) playbook the best social mechanic I had for a problem in the community was to declare it Anathema and hit it with the hammer for +1d6 damage..

I wish there was some more focus on the actual personal nteractions and community side. But it was my impression that is again a bait and switch game. It claims is about building a community but doesn't really offer much in regards to interacting with said community. My feeling for the intended gameplay was that it wants you to go into the forest, fight things, get loot and then spend it to buy something for the town. But that short last bit is not exactly a big part of the gameplay, so calling it the focus is a bit bait-and-switchy imo.

I know it, I've been watching them. But OSE is not quite right for me. So far I think the closer to what I want would be either AD&D2e or Hyperborea.

I am personally keep thinking about The Halls of Arden Vul, seems like an awesome thing to run. But I have to admit it's a bit intimidating due to size and complexity and I can't, for the life of me, decide what system to run it with. But it's been there brewing at the back of my head for almost two years now..

I've ran the game a few times with no railroading involved. They give you a basic form, but you don't need to follow that. Be prepared to add some challenge to whatever the mission is, but let them deal with it how they may. The main goal should be to give them opportunities to act heroically and to bruise and exhaust the mice a bit before they get to the next town. Life is hard for a small mouse and few brave the wilderness like the guard dies after all.
Checks force them to act their traits and to not just pay lip service to the character they claim their mouse to be. The players naturally won't want to use anything against their mice, they want to beat the game and succeed, but I would remind them of 2 things:

1. There is no failure in Mouse Guard, you might get a setback (which once you deal with your first goal is also achieved), you get to do it but will have a condition or you just succeed. So there it's not about winning or loosing, it's about how far will they go to win, a brave maouse guard, a hero of the guard, will go all the way, so the more hardship the braver, more respected they get to be.
2. The player with many checks gets to be the big hero for the group once they get to player phase and they can help everyone recover conditions and do other stuff.

So, checks actually do two great things in my opinion, make the characters look more heroic and make the player more popular with the group since they are the one helping them recover. So they act both on the character and player level.

Oh, and also, leaning into the traits actually improves your overall story. Fiddian's stubborness can become the stuff everyone at the table remarks upon, or Sally's kindness can be the sweet thing that gets her always into trouble. This works best in a longer game though, but it is something to keep in mind imo.