Why did you apply in the first place? Is there a particular reason why you can't just get a tourist visa & cross the border every few months?
Hmm, that's a tough one.
This can take from 2 up to 10 years or who knows how many... Can't do that on a Tourist visa, it's a "half measure".
You are right to reject the tourist visa option: it might work for a few quick visits to network and meet people, but it is not the best way to go if you are serious. And I have seen that when I behave in a serious and business-like way, I get serious and business-like results. (Off-topic: when I started being rigorous about claiming business expenses only for real business expenses and stopped telling half-truths on my tax returns, then I started making a lot more money. Correlation, not causation? Maybe. I put it down to an attitude adjustment.)
Back on topic. Did you prepare the E-2 visa application yourself or did you hire a U.S. immigration lawyer to do the work for you? Immigration work is 80% technical knowledge, 80% procedural skills, and 80% immaculate paperwork. That's why getting someone with deep experience counts.
(Disclosure: I have a vested interest in selling the concept of "hire an extremely experienced professional").
(Disclosure: I am not an immigration lawyer; that stuff scares me.)
Think about the category "L" visa. Executive of foreign corporation transferred to work at the U.S. branch. Set up a Swedish corporation. Create a U.S. subsidiary corporation. Decide to assign yourself to the USA to work.
Devil. Details. Etc.
These visa applications can be completed in 6 weeks or so -- this is what my immigration lawyer friends tell me.
Of course i had an experienced lawyer that took my hand throughout all the process... And we also examined all available options...
L type visas are not as simple as you describe. The criteria that have to be met are not suitable for a startup company. The killing requirement is that you (the employee that will be assigned in the US subsidiary) has to work in the mother company for at least a year.
... And let's not get into what the requirements for the mother company are...
But if your lawyer was so experienced, shouldn't you have been forwarned that you had a marginal case?
Did the UCSIS outright deny the application (which is a problem for the future too) or just ask for further documentation (which could be death by a thousand cuts too)?
However as you say, if you are looking for funding then it might be a problem, they don't say it but you can perceive it.
I'm wondering if getting the investor money helps to get your visa.
Does anyone know cases like that?
I think that if you get too complicated with your stories that's when you can get into troubles in customs.
EDIT:
I never stayed longer than stated on the I-95 btw
So it's the requirements + strong proof that you will create jobs in the US or your are a great scientist, artist, etc... or you have a lot of money to invest.