Nah, I'd rather keep the format in a single day, because it's a fun day for everyone to get together, feel the spirit of TISC, share memes and such, then I can use the next day to work and do other things.
Also, we've had many times seen cases where countries get 3-10 points in the second half of the contest, imagine being in 6th place, all excited, all to wait an extra day to find out that the RNG shuffled everybody that voted for your song in the first half of the competition.
Or the other way around, we usually end the contest with every country getting some points, whilst we can have a case where somebody ends day 1 on a zero.
I don't think that dragging it for two days would be necessary.