I've been using stiga Intensity for quite some time now. I love that blade but I decided on the korbel because I want something softer.
The Intensity is also light, 80 grams. I've also played with Donic Persson Power AR V1 and Stiga Clipper Wood. Never had an issue with any of them. From what I've heard here I should probably find a lighter one but what do you think? It should be fine, right? Or will it be too hollow feeling? I don't know anything for these blades...
Sorry for the late reply.
If you are using Stiga Intensity, then BTY Petr Korbel is fine then, in term of head heavy factor. Stiga, although not WRB type, still have a hole in the handle, so it is rather head heavy. For BTY Korbel, although I am not sure about the handle (normal or has a hole), but having bigger head (158x152 mm) and small / slim handle will make it head heavy. So I don't think head heaviness will be a problem for you.
Now the issue is regarding the weight.
You are accustomed to light blade, having used 80 grams Intensity. If you choose BTY Korbel, I am not sure about European Korbel, but Korbel JPN is usually above 90 grams. Can you get below 90 grams? Yes. I once had 87 and 89 grams Japanese Korbel (old black tag version). It is possible. But for many many years, every time there is new batch of Japanese Korbel arriving at the store nearby, the average weight is about 93 - 95 grams. So it will takes you quite some time to adjust.
How about Donic Persson Power AR V1? I had 2 (V1 version), and 1 is 76 grams and the other is 82 grams. Trust me, go for the higher weight. It is already a slow blade, having more mass will help you generating better power. It is a good controlled blade (AR+) but you will lose on the speed that you are accustomed to (using Intensity).
How about Stiga Clipper? OK, here I am talking about plain Stiga Clipper, which is Stiga Clipper Wood (not the WRB, not the Stiga CR, not the Stiga CC, etc.). Speed is faster than Intensity but not too much. But short game with Clipper Wood is very nice as it is soft and not bouncy. How about weight? Usually they are above 90 grams as well (because of the 7-ply construction), but I have 84 grams Clipper Wood and 84 grams Clipper CR. And more often I can get lower than 90 grams Clipper compared to those of Korbel.
Now with Stiga Clipper, the problem is that it is quite stiff, which is very different to the flexible Intensity. Intensity is modeled after Yasaka Extra Offensive (YEO). YEO is stiffer than Intensity but YEO is more flexible compared to a Clipper. So you are on the opposite extreme here (flexible Intensity vs Stiffer Clipper). You need more time to adjust then.
So according to me, you have tough choices here. However, Korbel and Clipper are popular blades. You can try both and sell the one you don't like for minimal loss. No verbal statements nor testimonies can really describe any blades, as individual preferences vary.