What do you think should be done about a service member that does not promote?

I see that you are a Paralegal SPC, which has limited promotion potential pretty much everywhere.
BDE and higher typically will have a spot, maybe two for a 27D NCO. It is not a good MOS for career progression.
I think that for your career to progress, you will need to reclass at some point.
Now for that bonus, keep in mind that just because the Army CAN take away your bonus, doesn't mean they WILL. Your 27D MOS doesn't go away if you reclass, it just becomes a SMOS. It takes a deliberate pay action on the part of the commander to collect that money back.
If you reclass within your unit and pick up a promotion in that MOS, talk to your commander and see if he/she is willing to support you for career progression. If the answer is no, you need to look for another unit anyway. If the answer is yes, problem solved.

I was in the same position after I re-classed. I return to my National Guard post and the E-5 slots were gone. The promise of holding one was worthless. If there is another job you wanted in the military now is your chance to get, however chance are it won't be available at your current duty station. You may want to see if there are any duty stations within a reasonable distance to see what opportunities the offer. Most if not all will pay travel pay and if necessary put you up in a hotel.

Some people are happy at their position, and are also needed there. I believe promotion should be considered by performance, not by an unwillingness to move on.

You also have the option of transferring laterally to another unit with a slot open for your mos just across the border in a neighboring state. We saw this all the time in our unit. You can also re class but in some situations the unit you go to can put you in an over strength slot which might be temporary until that position opens up. The very best of luck to you in your search for those buck stripes.

In AD, If the SM is basically stagnant-and has shown no interest in bettering themselves-then a bar to continued service may be warranted.

The more mos you have, the better for promotion. I had 3. Made promotions available, although it csn require changing units.

Yes, some people are great following orders, but are not very good at giving orders, especially in combat

I have seen 20yr E-4s, they will do their job, you just have to be told several times. Somebody had to be a E-4. Just stay in shape .

Find out the issue if there is none transfer them out! Soldiers want to move forward so stand up step up or get outta my way!

Their are time limits for all grades, there should be no issue. If a Soldiers fails to attend a required NCO development program there are many actions that can be taken to fix the issue, in the end it will be time that gets them.