With the numbers shown so far, it looks like blobbing is still going to be favored over any development. Blobbing costs 10 or 20 base monarch power per development (probably 30 if you insist on culture change) and weakens your enemies, while increasing development costs 50 base for the first upgrade, and it only gets worse after that. While in principle buildings could swing the balance towards development, I'm not optimistic about them actually doing so: 10 development per slot makes full-price slots extremely expensive, and it's uncertain whether there are more useful buildings than undeveloped slots, let alone useful enough to justify the huge monarch power cost.
My prediction is that blobbing will still be king and "tall" will not work well as an overall strategy, with development only useful in limited cases:
- You can't blob for whatever reason (coalitions, too many truces, neighbors you can't beat, regency council, etc.)
- Using only a few levels to round off provinces to a multiple of 10 development.
- An alternative MIL dump besides rerolling generals.