GMing in general, I'd say no.
GMing or even playing in a system where the characters have no real ways to decide the story except by convincing the GM that their ideas are good, I would say yes.
Pathfinder is a GM-intensive game where the GM needs to prepare a lot of things, from a plot to full-fledged statistics. It is a harsh role who's ridden with things to do, while the other players can easily just care about their character sheet and blindly follow your directives.
It might not be your group's playstyle, but it could happen.
In this case you'd be doing all the work by yourself, literally. By the way, that's a good reason for other players not willing to DM the game.
You also need a lot more system mastery than they do if you want things to run smoothly, from creating a challenge that's entertaining for a group of four minds to almost never having to halt the game to look for a rule. It's scary.
But the DM, or any GM in similar games (and I mean games with the same "may I ► y/n/roll" structure) is rewarded with two things: the satisfaction of managing to use such a complex system (good thing if you're into it) and the power of making the story develop as you wish, independently from the player's choices or successes.
This second part is dangerous, not only from the gaming balance point of view (the only way for a player to achieve something becomes putting some social pressure on you) but since you're the GM you might more easily realize that the other players have low to no in-game decisional power.
In my personal experience once I discovered the GM is supposed to only make it seem the players' decision have a weight in the story I've begun being less involved while playing PCs. For I want my decisions to matter, but that depends on how my DM manages the thing and since I don't read his mind I can't know if I survived an encounter because he let me win or because I was good enough (for example).
You also mention being "too" focused on mechanics. Why? It's easy to guess. The fiction has a low impact on the mechanics. You could play an encounter without caring who the PCs are or what their motivations are. You could reduce the swing of a mighty sword to a "I rolled a 24, it's 12 damage".
This is not a problem per se but if your new DM and group expects you to be focused on the roleplay aspect of RP+G (e.g.: "Don't care if it's ineffective, do what your character would do!") this could be a problem.
Remeber: optimizing does not mean being unable to roleplay, but sometimes makes it harder (especially if you need to justify the coexistance of certain divergent things in your sheet)
P.S.: It looks like the forums I wanted to link you with definitions of illusionism, an example of fiction with high impact on the mechanics (called "IIEE with teeth" IIRC) is temporarily down. I'll be back fixing it if I remember to.