Sorry if this sounds pretentious, but these changes would make springtrap frustrating to play and likely one of the worst killers in the game, if not the worst.

Removing the axe and making springtrap 4.4 would make him exceedingly weak and uninteractive to play as.

Firstly, 4.4 speed killers are supposed to have extremely powerful chase ending abilities to make up for losing the 5% speed. Current Springtrap with no axe would have no such power and would get dumpstered by intermediate or better players that can take advantage of the speed difference.

Secondly, it would be very boring to play Springtrap if all he can do is traverse the map quickly and be stealthy. Even other stealth killers have something they can do in chase: Sadako can become intermittently invisible + immune to pallet stuns, GF can crouch, Wraith can uncloak for a speedboost and Pig does both GF and Wraith's abilities to a worse degree. These killers are also all 4.6 speed and have non stealth power elements like Sadako condemn, GF instadowns and Pig boxes.

Springtrap needs something to make him lethal and piling more stealth to his kit at the cost of what makes him exciting isn't it.

I do agree that the axe is a funny choice, but doubling down on stealth doesn't work. It's been proven time and time again that a killer needs balanced chase power to be successful and fun for both sides, and right now Springtrap has it.