I can list down for you:

1. Expensive (even when compared to Thailand, who is also getting Hotstar). We currently only have 1 option at the time of this writing, and that is RM54.90 for 3 months. Thailand Hotstar will charge THB799 (about RM104) for A YEAR.

2. Substantially different from international Disney+ (I'll use Singapore as comparison):
a) No Premier Access. This means when Marvel Studios' Black Widow releases this coming July 9th, Malaysian Hotstar users cannot watch it, but Singapore Disney+ can (for an additional Premier Access fee). And because cinemas are still closed here (and probably will be for the foreseeable future), that's out of the picture too. Eventually Black Widow will be made available to Hotstar, but 90 days after its initial release date.

b) No parental controls. Singapore D+ app (which is the proper D+ app developed by The Walt Disney Company) allows users to set the content ratings for their account (G, PG 13, M18, R21 etc.). On top of that, it has Kids mode too. Hotstar (where the app is developed by this company called "Novi Digital", whatever that is) also has Kids mode, but that's about it. No other parental/content ratings settings available.

c) Labelled features that actually don't work. Movies listed in Singapore D+ are labelled with support for Dolby Atmos etc. and users actually get to enjoy Dolby Atmos. Movies listed in Hotstar are also labelled the same, but many have complained that in reality they only get standard stereo audio.

d) No English subtitles for a lot of content. That's right. Instead, we get Malay (which is nice, however with a big caveat as I'll explain later), Indon and Thai (for whatever reason).

e) Lots of censorship. Because of the lack of parental controls, or any content rating settings, Hotstar resorted to actually censoring content from the users. Techniques include zooming in the picture, and complete removal of the scene. I have also noticed that the Malay subtitles are not 100% accurate to what's actually being heard in the scene. For example -- "Are those testicles?" this line in the scene was provided with the Malay subtitle of just "Apa itu?" I don't know if that's censorship or the Hotstar subtitle team is just downright lazy.

f) Some movies are played back at 25 frames per second instead of the original 24. This means that the entire movie (and audio) is ever-so-slightly sped up. It's very apparent when there's music playing in some scenes. You will notice it. I haven't seen any of this on the Singapore D+ content.

g) No option to create profiles to share with family members. Singapore D+ allows you to create up to 7 profiles, which means you can share with 6 other people. Hotstar does not have this feature. You log in using your mobile phone (authenticate using SMS TAC number)
Those are the major issues with Hotstar that I can think of. I may have missed a few. But you get the idea.