Interesting new DLC concept. Years ago, I explicitely suggested such a DLC because there are many great fan-made scenarios of high quality, parallel to official campaigns.
So I am happy for Ramsey who totally deserves his own DLC! He created so many high-quality scenarios (also official campaigns) and pioneered new mechanics.
The price is definitely too high, though. Mountain Royals’ regular price of 15 euros also is too high, but it includes 2 new civs and the missions cannot be played via mods. Even considering that Ramsey’s scenarios are huge maps where you spend much more time for each (or may replay them with a different approach), it’s a mismatch. Plus, I still have older campaigns to play, so I just wait until its down to around 5 bucks (The price of TMR is already halved) 
I also hope Ramsey gets a fair share of the revenue, as he created these scenarios in his own time, if I understand it correctly. So MS should not charge high prices for his work or let him profit from it substantially.
By the way, they could also include the Aegidius campaign into the game as a part of RoR (free for owners of this DLC), which was criticized for good reason. Thus, Romans would also have a campaign.