Kind of glossing over the big downsides. Hyper Speed may give Sonic-level ability to get punishes but those hits are very weak, without the frame data to back it up. Hyper Buster is only really used for shield-breaking mindgames because even though it inflicts gobs of damage, most attacks are unsafe on hit due to there being no knockback (and no hitstun), unlike the original or decisive which are good in most circumstances. Not to mention the short duration on those arts means you're going to be spending quite a bit of time on the defensive rather than the other way around.
Smash and Shield are pretty much directly upgraded though. Hyper Shield in particular is probably the best thing about Hyper Arts, you don't just become impossible to kill, you basically won't budge when hit until obscene percents.
Good points. I think, however, that the short duration of the Hyper Arts lends itself to MALLC-heavy playstyle. The short duration I think also is a boon particularly for Smash Art, which you should only be using for a short time anyway. Should you become disadvantaged in Smash Art, the short duration will keep you from enduring sustained punishment.
The short duration I think is only detrimental to Speed and Shield; Speed Art benefits from long durations because it is perhaps Shulk's best art for neutral (though some would argue Buster is just as useful), and the neutral is where most of the game is going to played. The duration of Speed gives you less time to break the neutral and get a punish. However, should you get the opponent offstage, Hyper Speed's air mobility allows for some crazy edgeguards. You will probably need to read an airdodge, but if you do, you may be able to gimp the opponent at 30%.
As for Hyper Shield, your ability to tank for long periods of time will be hindered, but you can also utilize the increased camping potential of Hyper Jump and Hyper Speed.
Another utility of Hyper Jump and Hyper Speed is nair->Advancing Air Slash kill confirms. These are actually pretty easy to land from what I've tested, too.
As for the Hyper Buster hitstun issue, you can alleviate this a bit by taking on a more grounded playstyle. Hyper Buster down tilt deals 15% with the blade hitbox, and it can lead into itself. Two consecutive down tilts is practically half a stock when you have Smash down throw at the ledge. At early percents, opponents hit by down tilt won't even leave the ground, however, allowing them to shield. If they do shield, though, you can punish this with Hyper Buster back throw, which deals a whopping 20% fresh.
Nevertheless, you will sometimes get punished in Hyper Buster on-hit. However, for much of the cast, this punishment is well worth landing one 15%+ attack. Though, against characters with amazing throw-based punishes, it might not be. But still, even if you were to be down by 50%, it would only take three solid hits to even it up.
In a way, Hypee Buster Shulk is like Melee Ganondorf. It's basically Stray Hits: The Game.
Oh yeah, and as a side note, Hyper Speed's perfect pivot is just stupid. Perfect pivot up tilts for days.
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