Do you think it is non-trivial to dilute XCP, or do you think that trivially dilutable issuances can be investment grade nonetheless?
I am not exactly sure what you mean by dilutable - but I assume that you use it the way that the function of xcp can be copied within its own protocol.
I think you are right regarding that - this was true until last week. But even in this case it was reasonable to assume that the native currency of the protocol was more widely accepted and used than the newly created tokens. Even point 1 changed a little bit due to the ethereum fork and the usage of xcp as fee.
There is a second point regarding the crappy investment. I was with these guys since the inception of counterparty aka page 2 of the announcement thread. They knew exactly what they wanted to do and basically did it over the whole period of time. After ~3 month they left our beloved nest of bitcointalk to join the financial industry and tell the world what they created. They convinced worldwide quite a group of important people that it is worth taking a look - the effects of this can be seen now. Counterparty is regarding the quality of manpower/ development as well as the outcome of that the reference in the altcoin scene - we should not forget that it is 11 months old.
I raised over the whole period of time exactly the same question which you are raising now - what is this strange token xcp and why should it be worth something. They did not convince me (exception maybe now the with the ethereum fee) by purely economical reasons, even though they were also existent. but they convinced me by action. I stopped raising this question.
This is not xmr, which is definetely under all logical aspects the investment with the highest long term expected value which was started this year. But code as well as projects are driven by people, which is at least as important as the logical reasoning - for more information look in the msc thread .