Big water really is no issue for small boats. I dump my 15 footer with a 40 in a 12,000 acre lake all the time, and into one up above 30,000 acres every now and then. The biggest issue is not getting run over, as in the summer, the 12000 acre lake is the 3rd most used Corps of Engineers lake in the COUNTRY. Has more boats on it annually than lakes 3+ times it's size. I have used a 12 footer with 4 horse in the Atlantic Intracoastal waterway, and have plans to take my 15 footer down to the Gulf, for a bit of inshore fishing when I get the chance.
Biggest problem I would worry about on large lakes with electric only is wind. If you get stuck out in the middle with a heavy wind, you will get pushed around a bit, often in the opposite direction from the ramp, after a long day of fishing, when your batteries are exhausted. Don't ask how I know......