No electoral college means no campaigning in about half the states.
I have never understood that argument. Right now with the electoral college we have some states that the Republican will win except in case of a Democrat landslide. No one will campaign there. Similarly there are states that the Dem will win unless the Republican has a national landslide. Most of the campaigning will focus on the battleground states that are split nearly 50-50. If there was no electoral college, then a Republcan picking up an extra few percent of the vote in New York would help the national count, while now it might just shift it from 60D-40R to 57D-43R.
The main thing I like about the electoral college is that it provides a firewall against Chicago's (and other cities) quadrennial festivals of ballot box stuffing some call elections. Without the electoral college, tractor trailer loads of "found" ballot boxes would be rolling into Cook County's board of elections giving the Dem a 5,000,000 vote margin just in that county. Right now that will just shift Illinois's electoral votes (and like 1960 that might be enough to elect a president). With a national popular vote ballots from people across the country would have their votes canceled by the Chicago machine.