Nothing wrong with the 85 if bedded properly and Sako Metal plate is in the bin. Just bed with a T3 Lug. Neither 75 nor 85 will be as good as a T3 in my opinion. That is why you don't see 75/85 at serious competitions but a few T3's.
edi
I believe the reason you don’t see them in competition is much like most rifles designed and intended for the hunting market blaser/mauser/merkal/sauer. The Tikka T3 has been adapted due to the single action size allowing for a more cost effective design and manufacturing process by third party suppliers. The Tikka when first released could be purchased £550 and was a viable alternative to the far inferior Remington 700 that needed blue printing.
When you look at the 85’s features in respect of hunting it meets the design brief rather well.
60 degree bolt lift
semi controlled feed with a mechanical ejection allowing far more control loading and unloading, double stack metal magazine for top loading
Like or loath dovetail integral rail- Near Picatinny works very well
Excellent trigger with safety allowing bolt to be removed on safe and also locks bolt down when applied.
Action sizes apportioned to the cartridge group.

