The Smurfiest Wizard Ever!
No, Tough in our view is more than strong enough. We debated about making tough a CON +1 and +1 HP/level.Also, IMO the best fix to Durable is to combine it with Tough and call it a day.
Durable is one of those feats so bad nobody even bother to look at it. And i can guarantee that combining it won't change people's opinion on Tough.
Also, we use exhaustion a lot in our game, so getting to recover two levels of exhaustion is actually a big deal for our table. I probably should have outlined that before...
Finally, a feat that did combine Durable and Tough would become a very strong feat, especially for warriors. We utilize short rests enough that getting half or more of your HP back on each die is significant, the CON +1 is nearly universally useful (well, 50/50 depending on if your score is even or odd LOL), and a permanent raise in your max HP is big as well.
But, I know it varies from table to table. Others might look at some of the feats and be like, "What? People take that feat all the time! It don't need a buff!"