Math time:
#Solari
You need between 500 HP (level 1) and 640 HP (level 18) for the new HP ratio to compensate the nerf on Solari.
If you build Face of the Mountain, Sightstone and Redemption, you're already at 800 HP. If you go Eyes of Targon and Redemption, you're at 700 HP. Basically, if you go for the Relic Shield line of Gold items, Solari is still viable.
#Redemption
So the question is, is Redemption still viable too? To compensate the nerf on Redemption you need at least 15% increased Heal/Shield (not counting Redemption own's). If you go Windspeaker as a keystone or any Forbidden Idol item, it's roughly OK, a very slight nerf. If you take any two out of the three (Windspeaker/Censer/Mikael), it's a buff. I don't really think that Censer is good on Taric (does he have good AP ratios?) but Mikael can be a good situational pick. So you're kinda forced into Windspeaker. I believe it's Taric standard Keystone, but I'm not sure.
#Overall
I think it's still viable for Taric, but I don't play him personally, so I don't know all the subtleties of his builds. Independently of Taric's kit, typical builds that really benefit from the changes would be:
Windspeaker Keystone - GP10+Sightstone (or combined item) - Boots - Solari+Redemption - (fill out your build with your choice among Mikael/Zeke/Knight's Vow/Righteous Glory/Frozen Heart/any Tank item, take two if you picked the combined GP10+Sightstone version)
If you take FotM + Ruby Sightstone you get at least 3 item actives and the reduced CD from Ruby, but you get only 1 last slot, and if you don't take Mikael, it's a slight nerf to Redemption (and I believe Knight's is more generally useful).
If you take Eyes of Targon, you get two more slots so you can pick Mikael and another item.