I think that Bloodhound is pretty balanced honestly. They can only scan for a brief period of time, in a specific angle that leaves your back exposed. The ultimate is scary to face, but far from unbeatable. Sure you can trace people but the traces sometimes are misleading and can lead to an ambush, and if you combine it with the tactical, it can also lead to give away your own position.
Seer's ultimate is a complete dome that gives position of the team you are going to attack AND if another team will attack you behind your back. AND you get to detect people through the passive, combined with the disrupt + detect + showing shields and health. You could be giving your position with Seer's tactical, but the disrupt makes it impossible for the enemy to actually pinpoint your position.
The other recon are barely recon at this point, except for very specific tasks.
The Revtane + BH combos we had last season weren't as disruptive as a single legend this time.