I mean both systems have their flaws.
Without stamina you can constantly spam attacks with no real discretion, but you can be heavily punished for it.
With stamina the fights drag on longer and turn into more attrition based fights rather than an intense spar.
The spars now do not feel intense, they feel...boring? I do not know how to describe it. The old system spamming was punishable and was fun to use (in my opinion) and this new system slows down spars so much that it turns into people turtling because it's the best way to preserve stamina. If people run out of stamina you are not able to punish them properly because they can still jump, making it almost impossible to hit them unless you time your attack right, until they have their stamina back.
I've played games such as For Honor that use systems like this and it works when you are actually punished for running out of stamina, in this system you just run and jump until it's back.
+1 like I understand why the stamina bar is there, but it needs to be either increased or removed. As it kills the pacing of spars (in my opinion.)
Also, if you want to refer to non spars. The old system punished spamming by causing you to hit people around you with certain stances if you spammed, so it was balanced in that regard.
Maybe add only a few sabers that use stamina for formal spars and allows the previous system for others? I do not know if that is possible but that may be a compromise for some people