Honestly, given how they seem to drop off at higher levels I’ve been considering homebrewing different rules for summons.
My current idea is to keep the scaling consistent, so something like (spell level * 2) - 3. Level 1/2 would be the same (-1, 1 receptively), but then it’d keep incrementing by 2 every level up till a max of level 17 for a level 10 spell. Another option is (spell level * 2) - 2, but I think that might be too strong at the level you get the creature.
I’ll have to actually play with this rule at a higher level to see if it unbalances it, but IMO it looks like summons just get worse and worse at high level.
Vlc is also hosted in France, where software patents aren’t legal.