I finished this tonight. I've spent the last couple of days grinding, partly because I've been bedridden, partly because I figured that if the enemies in the area were giving me problems the bosses would slaughter me.
I read a guide that said to be around level 55, but they had a build and equipment to counter the boss, so I figured I'd have to be a bit higher. I ended up between 61 and 65 for my team, and I went and forged some better gear. That was probably all a bit much, I trounced a boss in about 3 turns.
I'm not going to say much more than that. There's more to do so I might go back at some point. I enjoyed it quite a bit all told. Its not a patch on 5, 4, 8 or even 9. It never quite gets going as a story, it's far too tame, too well trodden, without enough quirk. 8 wasn't exactly a gritty story either, but it had enough humour to make it stand out. The only thing 11 has to really make it stand out is how nice the world and monsters look.
Just to stress though, it's still a good game, it's just a bit of a by the numbers Dragon Quest game