Actually keyboard is pretty much OK and i like it more than hard to press scissors from 2012 MBP.haha "you only lose the keyboard" -- mate it's the worst keyboard EVER.
Only con is a failure rate.
But who really cares, if Apple will fix it for you 4 years after the purchase. Also with high end 2018 MBP 13 you are not going to see more than +20% performance with MBP 2020.
If your keyboard fails 3 times on you and it gets fixed by Apple, then they will replace your old laptop with MBP 2020 for free.
Cost of changing the gears is $900. Why would you pay $900 just for keyboard?
Main point of your upgrade is a large size of MBP 15 as per your words. I am also seeing people who sell MBP 16 to get MBP 13 2020. So in that case it may make sense to jump on this model. It makes no sense to change it just for keyboard if you live near Apple.Full disclosure - I just ate the next years depreciation on a 2018 MBP 15" and sold it privately. Couldn't wait to get rid of the keyboard! It was also too large, so my requirements changed but still
Also new Tiger Lake CPU is coming and it will be double the iGPU performance than Ice Lake.
So this 2020 model is really just a stop-gap. Next year's MBP will last you longer and will be worth the price to keep it for next years without even looking at new MBPs.