Both grunt & Porter make valid observations, although I will say this about the glue subject. It's been debated ad infinitum, but our personal experience based on A-B testing is that the sonic affects of the amount of glue used, in itself, is somewhat overstated. It is there, & how noticeable it is depends to some extent on the kind of glue used. For example, epoxy acts more like a bonding filler than a traditional wood glue. Accordingly, it's affect is more noticeable, but it's still fairly minor. The solid shell guys always list the amount of glue as being a bit of a deal breaker. I can't prove it either way, but my feeling is the affect is fairly small.
That said, it's what the glue is used to achieve that does have a big affect. Ply shells get their strength from preventing one layer from sliding against another, hence it's origins in the construction industry. The glue bond area is massive, & thus very effective in that regard. The more plies you use in a given thickness, the more rigid the shell becomes. Rigidity in itself affects pitch more than it affects the amount of resonance. For example, a bronze bell is very resonant, yet it is also very rigid.
The affect on resonance that is really noticeable is how many layers you chop the wood into. The thinner the ply, & the more layers you bond together, the less like wood in it's natural state it becomes. When wood cures, the various lignins & other elements in the cell walls harden. These hardened "channels" become mini resonance chambers that culminate to deliver the sonic voice of the wood species (some visual examples below). The more you chop these up into thin layers, compress them in a die, & stiffen them by mechanism of glue bond, the more of the original structure you remove. This makes the character differences less distinguishable between species, & increases the level of vibration input necessary to excite the structure.
Sorry, got a bit deep there
So, the basic answer is, all other things being equal, a shell with less plies is easier to excite at lower dynamic & will speak the fundamental of the wood species more prominently compared to a shell with more plies. The same difference (only bigger) exists again when you compare a 3 ply construction to a solid shell construction of the same grain orientation.
Treat this information with care though, because the moment you take your more resonant shell & bolt a ton of hardware onto it, the difference diminishes commensurate with mass. Also worthy of repeating - the benefit of additional resonance is not limited to head sustain/decay, in fact, that's a minor bi product. The big difference is in the tone of the drum in that first second of highest excitement. That's the very voice of the drum, complete with it's attendant valuable overtones, & by far the most noticeable element in side by side comparison.
Hope this helps,
Andy.