I honestly don't know if limited inventory space actually adds interesting design space to the system compared to Alpha.
I don't think the problem is inventory space. Now that items can be converted, you can always recycle inventory space and still get a net benefit. As well, many of the more niche items are small items and those have negligible inventory impact.
Blue Bead and Spoon in particular are great items in terms of their cost for effect. The problem is that they offer very poor density in terms of how much effect you get from your shops. For a gold-heavy run where complete buyouts are not uncommon (TT worshipper, a larger number of bosses, early gloves of midas), having a shop selling a low-cost/low-effect item is a waste.
Hmmm.... perhaps we should get something similar to the apothecary, where each shop randomly selects three different items. Take your pick, but you can only pick one
of the three and the shop then disappears. This would vastly increase our selection from the shops without increasing the maximum amount we can buy. This could also balance the translocation scroll; you randomly
get one of the three. Shoplifters can't be choosers