I have come across arguments that are pro dividend and value investing. A simple strategy that is attractive to me is the Dogs of the Dow strategy. It would be a good way to diversify from index investing--which I know is the preferred way on this forum.
Basically I want some extra cash to diversify beyond equities that are more capital gains than dividends. I want to look into better cash flow investments, or investments that decrease my expenses (non traditional investments) and diversify beyond the stock market at some point.
Diversification is surely a good thing. But you can still diversity within your Roth. You can move outside stocks by buying REIT funds for example. It is isn't crazy to have some international exposure. If you are looking for cash, there are preferred stock ETFs like PGF and PFF that pay nice dividends, but trade more like bonds. Another thing to consider is equal weight ETFs like RSP, which logically make more sense than cap-weight, and good evidence of long term outperformance (RSP hasn't been around very long, so you have to really dig to find equal weight backtests. They are out there, but takes some work). It is sort of mid-cap strategy, if you like.
The problem with the Dogs of the Dow (and its spin offs like the Foolish Four and Small Dogs of the Dow) as that it hasn't really worked post-discovery. It seems to perform almost exactly like the Dow itself. One problem is the Dow itself is an anachronism.
But let me throw this out there: Dividends themselves are anachronisms. Sure, you get the bird in the hand, but what do you do with the bird? You are still in accumulation phase, so you'd just reinvest the bird. My advice is don't worry about dividends, they are an illusion. Diversify yes, but don't worry about dividends.