24 can be fun, but you need to actually have a reason for each (beyond their official status). Out of these, I'm obsessed with one, love 5, really like 5, (aiming to) have input in 4, am fascinated by 3, can appreciate 3, have some negative associations with 2... and then there's English.
(ironically after categorizing the languages I got 23... forgot Spanish
)
In other words, I currently don't have a good reason to learn 8 of the languages, though I think eventually I'll give at least Lithuanian a try. And it will soon be 11 years since I started Finnish. Sure, I've been learning some languages that are not on the list, but I'm still very new to the "input 4", though all are related to my very strong languages.
I'm generally not concerned over "spreading myself too thin", but I really don't see how I could've learned 8 more languages over these years.
And yeah, would be great if you started some European challenge
I only know
this one... and before the Euro 2012 (football championship) I also decided to do a 6 week challenge in the language of the country that wins (Spanish).