If the problem is the lack of size in the rewards pool, then the solution would be to get more money into the pool. In general currencies gain value by 'exporting' stuff. In the traditional economy the more a country exports the more its currency goes up. If a community trading in a crypto currency can 'export' something that can be sold in USD, then the value of the currency goes up. So for example, if steemit sold advertising space, but only sold it in steempower then advertisers would have to sell USD and buy steempower, putting money in the pool.