The main idea behind summoner was that your minions do the damage so you can focus on dodging but with whips in 1.4 I think he should get a defence buff across the board.
Durendal should be S tier. With a technique called whip stacking, Durendal can use its 35% meele + whip speed bonus as a support for other whips like firecracker for desert tiger and dragon, and kaleidoscope for cell, terraprisma, blade and sanguine. It can even be combined with dark harvest's 50% meele + whip speed bonus for a whopping 85% meele + whip speed bonus, which not only benefits the summoner class, but also the meele class. With the right setup, the Terra blade + durendal + dark harvest combo can kill Golem in 5 seconds in Expert mode Also, Spinal tap combined with Snapthorn can give out 13 summon tag damage in total and spinal tap alone can shred the hungries up to Expert mode with obsidian armour, and stays strong up to post plant if combined with snapthorn and durendal so it should be A tier Watch this youtuber called Shyguymask for more detail
Perhaps you can add clips showing the use of the items instead of just random walking. It'd make it more interesting and fun to watch. Just suggesting😅
Dark harvest is easily a top tier whip as you didn’t mention its effect because not all whoops increase tag damage instead dark harvest (the only whip at that) to increase aoe damage as the main tagged entity cause dmg to spread from it to others effective increasing the dps even higher than kaleidoscope if you consider that. And by that I mean kaleidoscope is a +20 to minion dps and the dark harvest can do a +10*X amount of other enemies
While I agree that firecracker is S tier, it is not good to use it with low damage minion. The debuff uses a multiplier of minion damage, therefore the higher the minion damage the better.
your reasoning for firecracker wasn't great since firecracker + sanguine staff is the combo not blade staff???? durendal should be a tier at least makes blade staff like 10 times better. Spinal tap unlike you said is necessary since having your whip which is snapthorn which is a pre-boss weapon all the way to hm is pretty dumb.