Kirito's regen isn't useless, yes his hp regen isn't fast against opponents on his level, but his physical regen is, in SAO characters can be sliced through their torso, or have their limbs removed, and unless their hp hits zero their body stays together, on the other hand if you cut a part of Guts' body off it doesn't come back.
Also Kirito does fight tactically, he's frequently involved in developing strategies for Raid bosses, and in his battle against the salamander leader he used a smokescreen to distract him so ha could take Leafa's sword, and then used the Sun to blind his opponent.
And although Guts has him beat in versatility and experience (the gap isn't huge though), I wouldn't be sure about fighting skill. Kirito was able to match a nationally ranked kendo practitioner, despite being physically weaker and slower than her, and he was able to hold back an entire raid party of players very close to him in stats in a 2v49 situation. He's also developed his own style of swordsmanship, and plenty of unique skills outside of the regular systems of SAO. And he's maxed out his in game one-handed swordsmanship, duel blades, and martial arts skills, so there's that as well.
Also, for the argument of speed and agility, the whole purpose of Kirito's fighting style is to use his agility to dodge and parry fast opponents, he even does flips to dodge bullets and cuts spells in half. And if Guts using his canon to propel his attacks isn't affected by speed being equalized, Kirito can double his slash speed and rhythm with at least one of his sword skills, and all of them increase it to an extent.
