I thought it was interesting how they chose which characters to "die".
They "killed off" all of the new leads from Phase 3 (Dr Strange, Spider-Man, Black Panther), while keeping their supporting characters (Wong, Okoye, M'Baku, and potentially Shuri) - this will allow them to be more of a focus in Avengers 4, allowing for us to know them better, before their main characters are returned ready for the sequels (Spider-Man 2, Black Panther 2 - whenever it is confirmed).
They "killed" off most of the supporting characters from Phase 1 and 2 (White Wolf, Falcon, Scarlet Witch, Loki, Heimdall, Vision, Nick Fury, Maria Hill), while keeping their main characters (Captain America, Iron Man, Hulk, Thor, Black Widow) - this will allow them to be more of a focus in Avengers 4, as a swansong before their contracts end, and they are replaced by the supporting characters (assuming Captain America, Iron Man and Thor all leave at the end of Avengers 4).
The exception to the above is that War Machine is still alive, and they killed most of the Guardians of the Galaxy.
I would assume that the following will be additional main characters in Avengers 4:
•Captain Marvel,
•Hawkeye,
•Ant-Man,
•and potentially The Wasp,
But it would be nice for the following to also appear (even as a cameo - and with us being 17 characters and half of a Wakandan army down, surely there would be some screen-time available for them before everyone else comes back to nicely tie the whole MCU together before the Phase 4 reboot? It would also provide 10 additional "fighters" to replace the 13 "fighters" and half an army that we are down after Infinity War, as well as some support for Shuri (assuming that half of her team will have died as well)):
•Valkyrie,
•Korg,
•Nakia,
•Daredevil,
•Jessica Jones,
•Luke Cage,
•Iron Fist,
•The Punisher,
•Ghost Rider,
•Phil Coulson, Quake and the other Agents of SHIELD.
•I am discounting the Inhumans, the Runaways and Cloak & Dagger, as they would not have aired before last summer.
Not that I think that this would happen, but the first 3 and Phil would already be known to MCU Film Fans and The Defenders, The Punisher and even Ghost Rider would be easy enough to reintroduce to the film audience in a 5 minute scene of Captain Marvel contacting Phil, Phil saying "we need reinforcements" and then Phil speaking to the other SHIELD Agents on the Quinjet as they fly to New York to pick them up - similar to Phil introducing the other Avengers to Tony in his apartment in first Avengers film.
I have not yet seen the second half of Agents of SHIELD Season 5, but given the fact that Season 6 will not air until after Avengers 4 - they could possibly do something with them in Avengers 4.
Regarding California, it was weird watching Infinity War and then riding Mission Breakout a couple of days later, as although they are set in different Universes (MCU v MTPU), currently 86% of the main Mission Breakout cast are currently dead in the MCU (6/7 - only Rocket is still alive in the MCU).
