All of the expansionists' goals were achieved to some degree, but none of them was achieved completely.
Expansionists wanted to boost the American economy, increase the reach of US military power, and help to "civilize" the backwards peoples of the world. Taking an empire did give the US new sources of raw materials and new markets. But did these new territories really create a net benefit to the American economy? It is hard to know. The US did get more places to put military bases. But did this really improve our security given that our presence in the Philippines and Hawaii helped get us into WWII. The US did help the Philippines have a democracy that still exists today, but was that worth fighting against people who wanted independence? None of these questions has an easy answer.