You will still be able to beat him in a proper battle. Maybe I will tweak it so that he merely has a huge advantage. Also the rest of his armies will be at a disadvantage to Griffith and beast armies in autocalc so Gutts himself will probably get outnumbered a lot. I'm not sure I could tweak it so that Gutts has three times strength in autocalc or something. The Gutts you find early on and the Gutts who leads a kingdom are actually different troops so I can set the autocalc advantage to be different for each. Also I had a thought. I knew I wanted a Gutts kingdom to appear but wasn't sure if the same would happen if you played as Gutts. I can't think of anyone better to lead a separate rebel kingdom than Theresa herself. She won't be in the upcoming version but it would be cool if she started a rebel kingdom after meeting Gutts for the second time. You could of course just conquer her after that but it wouldn't be impossible to create an alliance with her. Even if only a temporary one
In 1.00 Gutts will declare war on you if you are an apostle. This will create a cool situation of three (or four if you count Kushan) powerful enemies tearing the regular kingdoms to pieces. Good luck surviving that massacre.
EDIT:Ok good thing you mentioned that when you did I hadn't actually set the autocalc advantage yet. It is set now at 5x.
EDIT:New news that you will all be glad to hear about. I am currently packaging the mod for release. This will not take long. Consider it an early christmas!
Also check out the screenshot thread for a little sample of what is in store. A lot of changes in this next patch.