It might depend on the context, but this word seems like a throwaway word, like "really/well" in English. I imagined this sentence to be someone describing someone, especially, for some reason, people joining an American football team. "What do you think about them?" "Nothing special, really." So, I'm assuming that "insomma" could have a similar meaning as well as an indication of summarization.
'insomma' can also mean 'in conclusion'... surely there is nothing wrong with translating this as... 'in conclusion... nothing special'... which would be much more of a realistic dialogue between people rather than an accurate phrase book translation... I'm ready to be put down.
In (in) + somma (sum). DL throws too many curve balls in vocabulary by fluctuating between primary definitions and conversational definitions. The primary usage of Insomma is 'in short, all in all, in other words.' However, conversationally, its usage can address conversation flow (e.g., well or so), exasperation (e.g., Allright!) and a measure of dislike in response to a question (e.g., Meh).