For new dungeons I don't need to say more I think because there are not changed for ages and would be nice to see something different ones for talents, gear and runes.
For experience and level up resonance would like to see something similar like 5-8 hours lore based hand'n'slash with new free legendary heroes as main characters. You can obtain heroes after you finish lore. There is almost no lore in this game. Goblins are just 300 stamina till every 59, 79 and 100 resonance level. If you don't like hack'n'slash idea would be fine to level up as it was till now with some adventures and lore. You can present new heroes, new schools of magic and let all players play them for a while. Guys to be honest there is a lot to improve when we talk about providing knowledge and information about updates and changes to the game. We all have seen everyone was confused about fixes and upades info even for S6. All data was't clear.
The last idea is about items and stats. Would be nice to see a more team play or if you don't want more team play then solo raids. For example 10 stages of pillars/trial like raids. You pick main stat of armour and you can select 2 substats. Then you go for 10 stage dungeon 3 times a week. Different mechanics and bosses where you must defeat them. Something like fey meander mixed with pillars but with more bosses. After 3 stages you get main stat, after 7 stages you get 1 substat and after 10 stages you get 1 main stat and 2 substats. If 2 people would go you can choose 1 main stat and 3 substats, if you go 3 person you can pick 1 main stat and 4 substats. 2 and 3 person raids would let us play not 5 but 6 heroes so it would be easier but require some conversation and would make this game more team-like. If you don't finish it you can continue with other ppl but mist start from the lowest stage. For example I'm at stage 9, you are at stage 8, and our friend is at stage 7. We all start at stage 7.