How about 3v3 instead? It's far more difficult to get 10 players together, and there's still no competitive PvP content for 3-man groups.
And no 1 on 1 pvp content
Don't say CD, that's at best pve with optional pvp
I think Corrupted Dungeons are a great start, but they definitely need more tuning.
Corrupted isn't 1v1 at the moment, is "1 vs 1 vs environment"
I do think 7x7 would be a better option, because its the size of a 7man portal to roads, witch will then give people training options.
That way we would have more synergy.
1v1 solo pvp -> CD (with a rework, to eliminate rats)
2v2 HGs -> 2man road portal.
5v5 HGs -> Arena -> crystal leauge.
7v7 HGs -> 7 man road portal.
I would however drop 10v10 HGs idea, it doesn't scale with anything.
A 20v20 HG could be super duper, but it can be abused, and i don't think the player base can support it.
My perspective, you need content for different group size..
The issue is the small groups..
Solo PvP is in bad state, you basically just have CD which is more PVE as PvP
2 players, you have 2HG and as 2 you can roam roads and take up to 4-5 man groups, also do road bosses which generate some content
As 3 you more or less just have open world or to split 2 do hg 1 CD
As soon as you have 5 most content is there..including crystals
So I would focus on 1-3 HG the rest already has significant content, the gap to fill is there. The worse content gap is solo pvp