From what they said about more spells being the single most requested change to warlocks, I can’t imagine a world where their spellcasting remains unchanged from the 2014 to 2024 PHB. But, I suspect (and hope) that they don’t alter their spellcasting structure too much. Just giving Warlocks an Arcane Recovery type feature that lets them get their spell slots back twice per day or something seems reasonable to me. Likewise with the druid, I think we’ll see a version of wild shape that still uses individual stat blocks instead of templates, but gives you a more limited number to choose from instead of pointing you to the MM.