Would you support a standard uniform for all branches of service? Why or Why not?

Oh hell no. Prefer each branch have their own. Now I am a retired Marine and my opinion dos not matter now, However, each branch is distinct in their history, regulations and uniforms. If I would have wanted to look like an Army trooper, I would have joined the Army. I was a Marine, each uniform was different from every other branch and it needs to stay that way. No disrespect intended, but Marines want to look like Marines.

I have said since 1972 that camoflage has to be relative to the relative situational environment. Start with a basic uniform cut with promotional limits(i.e., rank on chest ) but when one goes into the jungle needs more green color while desert will need more tan and beige. So it goes with onboard a ship needing more blue while planes and ground crews may need more gray color. Same simple consideration should be given to helmets or caps; High seas on outer deck might need a more precautionary color such as orange and red and yellow mix while armored track vehicle crews could use a subdued O.D. Green and beige and black mix. Infantry and Artillery teams may swap up a solid crush cap with a helmet showing a multi-cam mix.

How do we tell the difference from Navy or Coast Guard Lt.....vs Army , Air Force or Marine Captain?

One uniform. Affirmative

Absolutely not! A standard uniform would be destructive to morale.

Just fatigued. Branch nametapes. Marines wear 7 corner cover. The other services berets, patrol caps, & ball caps...

In general, a common uniform for field utilities would be fine. Different uniforms and/or modifications are required for different purposes, ie. aircrew, ship/sub, tanks/Amtrak's, APC's, etc.
I absolutely support that each branch should maintain their own dress uniform. The individual traditions of each branch are important and powerful. History and tradition needs to be carried forward.

When I was in all branches wore the same uniform, BDUs. Navy also had some kind of untility uniform fpr ships that looked like blue jeans.

For a combat uniform, absolutely. Anyone who’s been in combat in the last 20 years is all too familiar with the “who are THOSE guys?” question while on patrol. As a Cold War vet I remember vividly how we all wore the same uniform but with different rank and service insignia, but you could at least tell they were on same side before you were in rifle range. Now that we’re changing uniforms every 5-10 years and using different patterns for each service all while farming out our old patterns to allies and enemies alike we have pushed possibility of fratricide to a virtual certainty. I wish senior leaders would focus as much energy on combat readiness.

Absolutely. The pattern should be the same, but each branch should keep the things that make the uniform unique. Sailors and Marines should keep the eight point cover, and soldiers and airmen keep the Velcro on their sleeves. We should all wear our rank on our collars, though. Just sayin'...