My only problem is that you have little to do whilst not expanding. And if you want us not to expand and play "Tall", what the hell am I going to do in the mean time? Stare at the ceiling while waiting to get enough monarch points to go back at it. I was expanding like hell in the early game because I was unaware of this change, then i started falling behind in tech; me as a western country 4 techs behind in admin and 2 in diplo. And in hundred years i had only gotten little more than 40 provinces for myself, taking only claimed provinces, vassal feeding yet I still was falling behind. However it's not only me, the hole Europe is falling behind, in 1567 everybody was in the yellow, few in the dark green and only one or two in the slightly brighter green. I mean, not even your AI can keep up paradox.
For someone trying to do an achievement with so little time, i can't afford to sit idle watching my provinces NOT grow because i have to save it to catch up on tech and continue my rampage or waiting for my diplomat to come back after diplo annexing a 1000 diplo cost vassal.
So i thought it was me, and tried the "tall" gameplay with a free city. And i got bored in the first 15 years... There is nothing to do, you can't upgrade your provinces enough or else you will fall back on tech too, the buildings are expensive and you can only build few in a province early game. You can't go to war because you lack the cb to actually make something fun without conquering a city or vassalising someone and the missions get repetitive after a while.
But you sure gave a use to the speed 5 now...