5/4 grouping

[NeeraWM]

I believe this is context driven.
While I have been trained to consider 5/4 as either a 3+2 or a 2+3, more than one composer asked me to group it 4+1 in several occasions.
In 5/8 this is simpler: either 3+2 or 2+3.

[John Ruggero]

The question is even more problematic if we take in account different values combined.
What about a melody that sounds as: + +
Or: + + ?

The question seems to be shifting under my feet. I thought the original question was how to notate a long first note that takes 4 beats in 5/4 meter that has no internal grouping in either (3 + 2)/4 or (2 + 3)/4.

Now we have + + which is in a (3+2)/4 meter with a hemiola on the first three beats, and + + which is in (3 + 4 + 3)/8 meter.

In my opinion, rhythms like that impose their own division on a meter, so we are no longer considering 5/4 without divisions but rather composite meters and the rhythmic notation is fine as it stands.