I've been learning HD for the past year and just submitted a 45:39 run. Though if you compare the splits with the standard WR it tends to vary a lot.

HD isn't just a prettier version, there are some differences that change how the game is run and how fast you can go through certain portions.

• Load times much quicker on HD.
• HD is widescreen which gives more space in certain cases.
• Unconfirmed, but I think all throughout the game there are slight health and enemy balance differences.
• Also unconfirmed, but I think fewer lives are rewarded in HD, which doesn't make a huge difference in Easy but for Hard could change the run a lot.
• Baron Butterscotch doesn't become dazed in HD (much smaller window to bite his head)
• 3-phase robot in 2-3 doesn't shoot the top bullets, making it much easier to destroy its first phase.
• Donkey Kong section in 2-5 stops scrolling if you die (this is a minor one since you shouldn't be dying anyway, but possibly worth mentioning anyway).
• Still needs further research, but I'm pretty sure the alien in 3-1 will in some cases start the battle right away even if you don't attack it, allowing you to charge a shot (I toss grenades just to be safe).

I think there are more differences but I can't quite remember any more atm. Overall it's mostly minor differences but it might be worth splitting them anyway, since it's not just a simple port.

Loadings are a huge part of why WR was this high. If my run was done on PS2, my 48:05 would have been a mid 51. Since they are still the same game, I don't think we need to split GC and PS2.

HD, however, is a remake, and a remake is never the same as the original. Loads are reduced by better hardware, yes, but the differences you named makes sense for why it should split up. I support this idea.

Oh, and congrats on sub 46.