Wasn't the whole point of concentrate development--in fact the sole marketing reason for it--to give tall players more development without having to expand a bunch?
Once again, a feature that was advertised as a selling point for a DLC is just basically erased from the game.
Can you please stop doing this already. It's like you think up features without properly testing them. It took me one game to figure out that concentrate development created an insane mega-capital the way you originally designed it, and what we got now really is not a suitable replacement for the feature.
Make concentrated development go into the capitol state until the provinces hit somewhere around 30-40 development (increase this cap with tech/ideas), then spill into neighbouring states, and then states neighbouring them, et cetera. If you hit your 'concentrate cap' (i.e you only own one state), instead award ducats, government reform progress, manpower, or whatever other resource is deemed appropriate. It took me two minutes to figure out this alternative mechanic that is better than 500 dev capitals.