Very impressive.
I can see all of the Wallace comparisons. However, the one thing that I thought was most impressive about Wallace was his ability to scramble left and throw across his body accurately and with pace, without breaking stride. With most QBs when they scramble to their offhand you can concentrate your defense to that third of the field. With Seneca he was fully capable of rocketing a ball back to even the far hash mark with no loss in accuracy or velocity. It looked like his upper body was attached with a swivel to his legs.
There weren't a lot of examples in those two videos of Mitchell passing when scrambling left but when he did he seemed to almost exclusively pass toward the left sideline or if he did pass across his body, hop which can definitely affect velocity and control.
This is picking nits, though. He is very impressive. It is definitely exciting to watch the kid find a hole and make everyone on the other team appear to run backward. It is also cool to see him slide, step up or actually full scramble without his eyes ever leaving his receivers downfield.
I am less concerned about his height and more about his hands. Remember, the biggest thing Seneca had going against him was his small hands. I still can't even think about that OU game in the cold rain...
I will be holding my breath until he makes it on campus. It appears he can be a difference maker.