In today's modern military, would there be any benefit to an enlisted structure similar to that of the past?

Yes, I totally agree..

I have come across soldiers in my career who could both lead and were subject matter experts in their MOS. But, I have also come across those who were technically on point yet couldn't inspire anyone to follow them out of a paper bag. Also, I've met soldiers with great ability to lead, but were a disaster when it came to the finer points of their MOS. I think we should bring back the old rank structure that way the army could put people where they could perform best.

Some in charge don’t belong there . But our current rank structure is fine.

Our current rank structure has been fine for over 30 years . Why mess with it

Yes, let's face facts by the time an E-4 Specialist is ready for promotion to E-5 they have spent all their time in their field, mechanic, personnel, truck driver, engineer, etc. and have become proficient in their job and duties. Now some will be ready for a leadership role, but most want to stay doing what they are doing. Promote them to the position they are applying for.
Now combat arms needs to do away with the specialist E-4 and make them NCO ranks, That is where you really need the leaders who can take over when needed to the higher ranks. This is where the SGTS and officers need to mentor and identify who under their command will make a good intelligent leader

The old spec rank was not great for senior grades, make tech grades and juniors grades can see they are tech NCO.s The from ol' old enlisted and then officer

This was based entirely on your MOS, not your leadership ability or lack of it. At a certain point, your next promotion made you an NCO.

In some of the service MOSs there may be ten Sergeants working in a section.

In the old days one would be a Sergeant the rest would be Specialist 5.
They were all equally capable but one was in charge you knew who that was just by the rank ialist on the sleeve.
Same as if you walked up to a bunch of E4s if one was wearing Corporal and the rest had Specialist you know who can well better be supervising not playing.

Well when I came up we had all the spec ranks. You didn't have a spec ín a squad leader position. Then again we also had all the warrants also. You couldn't fly if you weren't an officer or a warrant. Our brigade had a platoon of specs. Most were back office weenies. No disrespect meant...just what we called em. I don't understand why you need a hard stripe over accounting or in hospital or any of the other back office/non combatant positions. Hard stripes were always combat troops. It's sorta how we cliqued back then. You know no frat rule. Unofficial of course. Maybe it was our unit or army wide I really can't remember. My mind is not what it used to be. Hell I didn't even know they had done away with the specs.

The only rank I think the military should bring back is the corporal rank. Other than that, the structure is designed to advance soldiers into leadership. Those that don't want to lead don't have to go for their E-5 stripes, though I doubt there aren't many they would refuse them. With rank comes additional responsibilities and leadership. Once you become proficient in your MOS, your rank goes up in recognition of that level of proficiency, as it is expected that you will help those less proficient. That's leadership.