Is that just an assumption or are you just making a baseless claim? Certainly removing legislative discretion over specific spending would greatly increase executive power.
Once and for all, earmarks are not some sort of system whereby people can pass secret legislation. The are legislative direction on spending.
The definition you have heard of them before is not their true definition. Although certainly they would be useful to pork kings, since anything that a pork king could pass would probably be through an earmark, since "spend the money from the legislative bill on this bridge to nowhere" is an earmark, but there are much better ways to eliminate pork than eliminating legislative discretion on specific spending.
"Spend this money in the budget on an interstate between this new big city the president doesn't like because it's too liberal and this other city" would also be an earmark.