Pretty excited for this one! I wonder what the emergent changes will be for fortress mode?
I'm hoping either this release or subsequent rounds of bug fixing will address invader frequency and pathing problems!
40.X fortresses get old pretty fast from lack of invaders, or gluts of undead that can't find their way into the fort.
Invader frequency, in as far as addressing the pathfinding bug, has been addressed. You can also play with invader numbers in the .init file now.
That won't address the problems of goblins just deciding to attack someone else instead of you, so it may still be too infrequent for a lot of people. Especially if the standard invasion population cap, which a lot of people complaining don't seem to know about, remains at 80.
edit - I guess the problem is not 'how to add lots more sieges', that's pretty simple - produce them out of thin air like in previous versions, but more like 'how to make existing goblins want to attack the player fortress multiple times a year as opposed to any of the other, much easier to attack targets'. From a goblins point of view it makes no sense at all to attack a player fortress.
And, much as it's difficult to accept for those who love their endless repetitive sieging, that's not likely to be addressed until at least the starting scenarios arc.
Still, now that the pathing bug is fixed hopefully all you have to do for a Fun embark is park yourself near some goblins. Oh, and lower the population trigger, because almost everyone's militia is near legendary by the time a fortress reaches population 80. Other than that I'm pretty sure tougher goblins are well within a modders range.