Should the Army bring back the Specialist titles?

Yes, they should or perhaps bring Technicians back since the Army seems to want every one E-5 and above to back a NCO. Specialists ranked between PFC and CPL, at least back in the 1960s when I came in.
Most I dealt with, above SP4, were either cooks, mechanics or medics and their ranking never really came into play for details, as their jobs made them exempt.
As far as their relationship to other ranking folks, it was kind of like WOs. They rank between SGMs and 2LTs, but WO1 & CW2 were treated like company grade and CW3 & CW4 like field grade. SP4-6 were like NCOs and SP7-9 like Senior NCOs. Never laid eyes on an 8 or 9, but saw a lot of SP7s at hospitals.

I do not think bringing back the Specialist Rank structure is a good idea. The SP5 - 7 was discontinued right at the time I attained SGT. I got out of the Army for a long time and came back in. I would have a really hard time wearing "soft" stripes. In my experience the soldiers in a medical MOS were usually the one who wore them. I am a medic and while I have not gone to war, I have lead troops. We as NCOs need to be able to step up and learn to do what is expected of us in any given situation. Our mentors, the people above us and our peers need to make sure we have the knowledge, expertise and chance to lead. Don't assume we can't, assume we can until it is proven we can't.  It is easier for some than others.

Sir, while  I agree with you about the fact that the SPC4-6 ranks were useful, they really don't fit the modular BCT structure of the Army today.  With a smaller, better trained force, I agree with everyone having to be a leader.  It doesn't matter what MOS you serve in, everyone will find themselves in a leadership role at one point or another.  Down range, you could be on a convoy that gets hit, and anyone on the convoy has the potential to need to take charge.  We are a leadership based organization, and while I agree with the notion of technical jobs and SPC ranks, I don't think that we will be able to fill those positions in this downsizing Army.

I don't know, None of the other services ever had SPEC ranks. And there was a reason we got rid of them. I say let them stay dead.

I hate the SPC insignia.  IMHO,  it is also ugly and it is hard to like.

Yes. There are NCO's in Senior Leadership positions that dont need to be there. The specialist ranks would take care of this

YES, they should not all soldiers are capable of leading other soldiers! We will always need expertise based on ones career path and interests!

absolutely they should. As you say, not everyone talented in their MOS is cut out for leadership.

Absolutely

I loved being a Spec/5, but I was a medic.
My last position before retirement was the 2d SSG in a Trans. Squad - Not the Squad Ldr. - in the old system I would have been a Spec/6 - looking at the whole structure of the truck company - the 2d E-6 in the squad would have been the Squad TruckMaster! - in those last years, with my secondary as a mechanic That Is What I Was!