A few thoughts... First, there is a 20k adgroup limit per campaign.
Second, going in you should assume that 80% of your long tail keywords will not get any impressions.

That being said, this is a common strategy with several different ways to execute on it...

1. The rule of thumb when building out campaigns is being mindful of how you will optimize and manage it. I like to ask myself...Will my ad copy or settings change if I separate these keywords into new adgtoups? If not, group them together(unless you can't on the build out).

2. Become intimately familiar with filters, segments, columns, labels, and dimensions or else managing it can become impossible.

3. There are two common strategies that people use similar to this... One is putting all matchtypes in 3 dif. Adgroups and negated out the other matchtypes... The other strategy is starting a beta campaign with only broad modifier and when you find converting queries in your search term report you move this over to an alpha campaign with higher bids.

Putting both together in the same ad group would be pointless.

As for the effectiveness of using any of these strategies it would really depend on the effort involved in building out and managing it and on how crucial it is you don't miss out on any queries...

I would be happy to explore your specific situation if you call me.