I've seen the posts about accessories being bad and needing a buff, but I think that they are doing great. For example, the putrid scent and flesh knuckles combo accessories are great. One makes enemies target you and one doesn't. I have definitely seen the effects of the putrid scent, as when I was building a mob grinder I had to take off my mana flower + putrid scent combination (forgot the name lol) because the enemies would just not target me and fall into the lava. I haven't used the flesh knuckle accessories, but since the putrid scent ones do such a good job at keeping enemies away, I'm assuming the same goes for the flesh knuckles (but opposite).
And for the summoner class, I don't really know but the whips seemed to do just fine for me. I went mage in my master mode playthrough but I used whips as an early weapon when I didn't have mana. They did really good and I think you can just use them for a summoner class. Especially the one dropped by the Empress of Light or the Dungeon drop, they two shot certain enemies at night. There of course isn't any good early summoner armour so I think that the pharaohs set should be made into a summoner armour (since it's so annoyingly common). Maybe just +10% increased minion damage, +5% increased minion crit damage, and +1 minion for the set.