Presidential Election Term

Yeah! If it works, fix it till it don't.

What problem would it solve that doing away with the electoral college wouldn't?

Eggs-acolytes!

The last year of a Presidential term is spent running for reelection. It also becomes hard to get anything through Congress because the opposing party is trying to deny the sitting President any "wins". I really don't want to make that more common.

I would prefer one six year term for modern presidents for the reasons you mention.

It is difficult - better: impossible - to compare the terms for US presidents with other countries (head of government and head of state are two different posts elsewhere). (List of political term limits)

But if there's a six year term for modern presidents, what should the elections for the House of Representatives and the Senate look like? Every two years for one part as before?

Apart from campaign finance reform, I'd leave the congressional elections alone. The big problem is the with the presidency – four years (more like three years of productive work and one to campaign for re-election) is barely enough time to get things accomplished and second terms usually get kind of stale.

True, but when you compare American campaigns to those in other countries, you'll notice that period in the USA lasts an absurdly long time.
(Other countries strictly limit election spending, and if campaigns don’t have ridiculous amounts of funds pouring in, they have to have shorter campaigns. But that's a different topic.)

Yup...with the early preparation and search for seed money, through the primaries and the fall campaign you might have a run for political office taking nearly two years. Campaign finance reform is urgently needed but will be strongly opposed by the GOP and probably struck down by a conservative judiciary.