Li Shenron
Legend
I wonder if surprise could mean "you go first", or maybe "you get two actions in the first round".
"You go first" is basically how it went in early 5e playtest packets. Surprised creatures got a -20 penalty. WotC said that players didn't like it because of the calculation needed, but I think the problem was more that "it doesn't look nice to have negative Init" rather than the calculation itself, which is trivial and needs to be done only once per combat.
To be precise, it was a little bit less than "you go first" because the penalty could still occasionally result in some high-Dex monster with a lucky roll to go before an ambusher with low-Dex and poor roll.