The Cowboys agree with you, FWIW.
The three categories of QB you are looking for in a backup are: 1) trusted veteran, 2) young journeyman with something to prove, and 3) developmental talent-- most importantly each has a different price tag and different level of demand on coaches. If you are serious, you really shouldn't have more than one category 3 on your team. I personally don't like category 2, but it's a thing.
Milton remains in category 3 while Howell is now officially category 2.
I think Milton may never improve, but am willing to admit the jury is still out. He's not as poor as Trey Lance was, but it's like he's always armed with a bazooka when much of the time he really only needs a shotgun or handgun. No touch and poor accuracy.
Howell showed many skills during that year starting for Washington, though he also owns a lot of those interceptions. I mainly think he lacks in stature and does not directly compare well to others in-person.
What made him attractive to Seattle, Minnesota, and Philadelphia was his rookie contract and potential as a category 3, but the second they each drafted their own (some dubious) category 3 guys, they traded Howell away for whatever they could get.
So what I really dislike is heading into year 5, we only have that one very uneven year in Washington and a college career to gauge Howell by.