So apparently the summon timers are brand new to 2.0
I havn't played since PoE came out and now I started playing again because the expansion campaign came out.

I bought up and kept every summon per rest totem I could find because I loved using them!
However, now they only last around 5-10 seconds!
This is HORRIBLE because they only last long enough to cast one spell or do a couple attacks.

Anyone else find them vastly less useful now?

Yes, they reduce their utility with the timer, mainly because is too short, however, the number of totems has been duplicate, in the white march's area you can find all the totems again. (Of course this is not useful, as seem theire is a limit of summon and many times I lost the ability to use the summons )

However, now the summons are useful only to break the lines of the enemies or for taking down quickly the casters.

P.d. the dog (Can't remember the mantle name) seem to be infinite, the last summon that you can use as your pet (this is new) seem to be infinite too (but probably is a bug)

Ahhh that's interesting to know.
I'd rather just have the summons be either infinte time or looooooong summon time.

sounds like a reasonable nerf

Until end of encounter would work.