I liked 1 because the hidden blade, now hidden blades, weren't OP as stuff weapons that 1 hit killed no problem.
The sword was actually useful since in 1 the hidden blade could only counter attack and not block hits.
Plus there weren't so many gimmicks like smoke bombs and crossbows which was also ridiculously OP compared to the gun which becomes obsolete after you get the crossbow.
Oh and I like AC1's era more since it feels more medievally without the guns.