PAMIAPSyn sounds remarkably similar to something I have suffered from for years. I didn’t realize what it was until I found out about Whoa. I have called it MIAO (meow?) - Multiple Instrument Acquisition Obession.
Mine started with just string instruments. First the Bass, which wasn’t satisfying so I moved on to the Guitar (I own four). I pretty much stuck with guitar for years until a friend gave me a Mandolin (I now have three). The mando has since become my main axe. Still love and play the guitar though. I began to pick up slide guitar, not really a new instrument, but a very different way of playing the old one. This lead to a Dobro. A couple years ago I discovered the Bouzouki, nad now have one of those too.
A Bohran was my first non-string instrument. I am the source of all those jokes you hear about it - my playing that is… 
I just bought a Doumbek, which I am finding a bit easier to play.
My first Whistle came about two years ago, but I didn’t really start seriously playing it until a about 8 or 9 months ago. I now have nine whistles. I also have a Xaphoon.
I really want to get into the flute so I can play in different keys with greater ease. I think it is a more versatile instrument. Half-holing and cross fingering is fine, but why use a brick to drive a nail, when you can use a hammer. Don’t mistake this as meaning I don’t like the whistle, I still play it everyday (all day every day my wife would say…)
As far as competence on all these different instruments goes, I think it depends on who you are. My brother in law is a band teacher, belongs to a jazz band, plays trombone and tuba, but has the knack of being able to pick up just about anything very quickly. Practice time is a big factor. The nice thing about the whistle is it is so much more conventient than a big bulky guitar. Practice comes easier.
I have to agree with the general consensus this thread, that we can usually “master” one instrument, and just have fun on the others, which is what I do. I do believe, however, that it is possible to become fairly proficient on say a string instrument and a wind instrument.
In conclusion, I have to say that Whoa is the least insidious of the various forms of obsessive acquisition disorder - It is so much cheaper, and doesn’t take up nearly as much space.
Forgive my rambling on so, but this is something I have a serious problem with. I have really had to deal with the issue that sometimes we spend so much time collecting instrument and not enough time playing them or learning to play them.
I think however I have terminal MIAO - Weber mandolins just came out with a new “portable” mandolin, similar to Martin’s backpacker mandolin. I gotta get one. I need it. I want it I WAnt It I WANT IT. I think I could actually get both a low D and a soprano D in the case as well - I would be in heaven - Mando and whistle wherever I go.
Blaine
