Good question. It does seem to be pretty powerful as targets go. Having had a quick look, T: Sight seems to have been replaced by a R: Sight, T: Group combination. There is even one spell there (Vision of Heat's Light, ArM4, page 136) that now uses T: Vision, i.e. it alters the target's sense of vision. To my mind, this describes the spell intent far better than the 4th edition version.
No skunks in Mythic Europe (New World only). The closest would be a polecat, also called a foulmart due to its stench. I've smelt both -- while my pet ferrets (both male) can be stinky at times, they in no way compare to a skunk at full volume...
The ArM5 magical senses target of Vision is not the same thing as the ArM4 target of Sight.
ArM5: Vision: The information comes through the sense of sight. (Based on: Intellego spells can grant magical senses to a person.)
ArM4: Sight: The spell affects everything within sight of the caster. (This still isn't quite what I personally wanted when I was thinking about this, which was a "target" that affected those who happened to see the caster, maybe I just need a new target.)
Okay, first, to be clear to anyone new reading this, the 4th ed Target:Sight had nothing in common with the current 5th ed Target:Vision. 5th ed T:Vision affects a sense, while 4th ed T:Sight affected everything the caster could see. Huge diff. Huge.
Now, getting back to the OP...
To answer the OP... for a mage to be able to fly up and nuke everything within sight - say a 30 mile/50 km radius, almost 3000 sq miles or 8000 sq. kilometers (and MUCH more on a good day) - yeah, that's could be seen as pretty overpowered by some.
All the RDT's got reworked in 5th, plus new considerations for "volume/numbers created" (which was not addressed in 4th), wards, Target:Sense, and other quirks to make all the spells "make sense" under one single umbrella system. Gone also are Target:Small, and many of the "special" RDT's that plagued 4th - and gone (or largely changed) are a few spells that simply did not make sense w/ the new system (or perhaps even in the old, ahem).