Its ok. Dr Strange will somehow go bk in time and save the dead ones. Spidey etc, as there can't be any more spiderman films if he stays dead huh? Thor may make a sacrifice, as it Hemsworth last outing as the God of ⚡ and Tony Stark is surely nearing the end of his tenure too? Avengers 4 wil be interesting nonetheless. Get Deadpool involved. That'd be cool
They set Infinity War a couple of years in the future, which is their get-out-of-jail-free card for the next few films.
I thought it was an absolute triumph. A proper war film, with multiple battles and strategies and the loss of some main characters (Loki 😢). Thanos was portrayed wonderfully, you could somewhat sympathise with his cause. The ending was perfect (but like you said, time stone them all back to life otherwise what's the point, Thanos doesn't need stopping/defeating now, he's won).