I'm brand-agnostic (as people may have discerned from other posts of mine). Each brand has its pros and cons, which also vary by model. So to address some of what you mentioned, I don't think Korg upsells anything from Kross (and Roland upsells plenty, also varying by model). Both brands have models with varying amounts of menu diving. There are plenty of bad manuals to go around. As a whole, to generalize some, I have found the manuals that come out of Korg Italy (e.g. their arrangers, the SV2) to be better than Roland's manuals, but Roland's manuals (though not great) better than other Korg manuals.
As you point out afterwards ("the built in sequencer is only a looper"), those models are not really workstations. For a Roland alternative possibly in budget that does have a full linear sequencer, there's the possibility of a used FA-08. The Roland does have a nicer sequencer workflow than the Kross as I understand it (addressing your deep menu diving comment and also Biggles' RSI comment).
For boards of the general type being discussed here, though, for my own needs (which do *not* include sequencing), I did prefer the Juno DS61 to the Kross 61, primarily for interface and at least some implementation of seamless patch changing (and would prefer the Juno D for those reasons as well). I also preferred the Juno DS61 action over the Kross, though that's damning with faint praise. Another knock on the Kross 88 is the physical size. The DS88 wasn't svelte, but the Kross 88 is a boat. Though the DS88 was too heavy. But Kross also had its advantages over the DS... besides the sequencer, the Kross did beat the DS in MIDI functionality, the Kross 61 was wonderfully lightweight, and I did prefer some of its sounds.
Related, and getting back to the OP, I suspect that the Kross will generally sound better in its acoustic instrument emulations, than the FA (which, outside of its SuperNATURAL virtual analog and handful of SuperNATURAL acoustic tones, uses the 25-year old XV-5080 soundset, though you can also download some slightly newer SRX-based expansions for it). But the FA will again win in interface/ergonomics, some amount of seamless sound switching, and does have potential sonic advantages at least in some of those SuperNATURAL categories.
But if he doesn't want to look for something used, and really wants an 88 with the workstation-style sequencer built in in that price range, I don't think there's really an alternative to Kross. As you kind of point out, with so many people moving to DAWs for that stuff, boards aren't emphasizing that kind of sequencing so much. In fact, even the Fantom-08 the OP mentioned doesn't have a full workstation-style linear sequencer.