The person who made these two decisions should be fired and once on its way out, should pack the guy who had final go for the 6DII sensor's decision.
I'm not going to defend Canon on the video decisions. The RP should have 1080 24p as well as 1080 crop modes. There's no technical reason for not having them. If Canon is afraid that newbie users will get poor footage with 24p (panning or monitor frame rate mismatches) then they can hide it behind a custom function just like extended ISOs. 1080 crop should be an always available option that is automatically engaged with an EF-S lens attached.
As for 4k: it's clear that Canon has a sensor readout speed issue even with the latest 5D IV sensor architecture. That's what's killing them on FF 4k, and 4k + DPAF at any crop on lower end sensors (FF or APS-C). They're probably still working on replacement sensors that can handle the required video readout speeds across the line. (I debated this with someone on this forum at one time, but now I forget who. On reflection I'm convinced they were right.)
Given that reality, if they were going to release the RP right now then they had to use an existing sensor design. The only candidate is the 6D2 sensor
unless they were going to drop down to 20mp and use the 1DX2 sensor.
Maybe they should have done that. Though we associate the 1DX2 sensor with the cost of the body the sensor itself likely costs little to manufacture at this point. Canon marketing would have a fit because a cheaper camera would have better video specs than the 5D IV or the R. But given the stills limitations on the RP body you're probably not cannibalizing 5D4/R sales so much as adding to them. At the same time you're preventing video guys from fleeing to Sony or Fuji. It might cannibalize some 1DX2 sales (those that are exclusively for video) but as Canon Rumors Guy pointed out, in business if you don't cannibalize your own products a competitor will.
As an example, I would have preordered an RP if it had the 1DX2's sensor and video specs without any stupid compromises to "protect" the trickle of 1DX2-for-video sales. As is I will pass. For that matter, I would probably buy an R body at the R's price point if it had the 1DX2's sensor and video specs. Maybe Canon should have done that instead. Maybe they still should since they could throw it together fast and it would stop the bleeding of EF lens owners who want solid video.
All of that said: I have and will defend the 6D2 sensor on stills. If you're a stills shooter looking at your first FF the 6D2/RP sensor is notably better at low ISO than the 21mp sensors Michael Riechmann was using to produce large fine art prints back around the turn of the decade. It's far and away better than those sensors were at high ISO and competitive with other sensors on the market today. It's also a good 1 stop better at high ISO than the other cheap FF option, the Sony A72.