I'd love an Alchemy remake. I've said it before, but I think Alchemy's lack of popularity was due to how bad/wacky/slow/redundant its cards were, rather than due to the Potion gimmick itself.
Like most people here, I'd keep unchanged Uni, Vineyard, Apothecary, and Apprentice.
Transmute and philstone need some serious fix.
Possession, do we really need it.
Herbalist could also be replaced by something more interesting.
Familiar definitely needs a price review. Alchemist and Golem too, maybe.
Pool should lose the inspection part.
Yet, I don't think these changes would make Alchemy satisfying enough. Alchemy also suffers from having many cards filling the same role (Alchemist, Pool, Apprentice and Golem), so I'd take away a few. Moving Alchemist's bonus to another card could make sense. Or combining it with noninspecting Scrying Pool. Golem is also a weakish link, I wouldn't be too sad to see it go for variety's sake. Apprentice and Pool are clearly the memorable two in there.Then fill up the blanks with card-shaped things that make their Potion cost interesting, and that appeal to a variety of decks.
From the single-customer point of view this would probably be a good purchase, but the larger picture might be a bit bleak for RGG and Donald - Alchemy has such a bad name that many people would be wary to buy Alchemy II.