I like an open draw on a pipe. Missouri Meerschaum consistently has the best open draw I've experienced. I have a few briars with a decent draw (Sav, Weber), but nothing close to a MM.
First, what other pipe brands have open draws?
Second, how can I open the draw on a pipe (as I have about 2 that are annoying me and think the issue is fixable with a nominal skill set)?
"First, what other pipe brands have open draws?"
Castello, outside of that practically the entire Briar pipe industry has unanimously settled on 3mm drilling.
If you want anything different then by far the best option is to get your own tools.
3/64" diameter
vermontfreehand.com
When it costs all of $16.50 for the two drill bits and slotting tool you'll need to open the draft on an average pipe (assuming you only need the shortest drill bit, but 3" is a very common stem length), it's hardly even worth the cost of sending your pipe in the mail for someone else to work on.
Buy some basket pipes or burned out estate pipes for practice and from then on you'll be able to tune all your favorite pipes to whatever type of draw you desire.
Bent stems are more involved because you need to straighten and re-bend the stem, but if you're fine just smoking straight stem pipes for a while then opening the draft is not expensive or complicated.
I will emphasize that the high quality Taper Point drill bits are practically a necessity for this job, normal tip drill bits wander way too much.
And the worst case scenario if you do blow up the stem is you get to send the pipe to a professional repairman to have a stem made to your exact specifications, which is probably better than buying an entire custom made pipe in the first place.