Heres my opinion. If bitcoin goes on to have a giant speculative bubble similar to past ones. First there will be a giant sucking sound as alts all fall in value when bitcoin really starts rising. At some point alts will be too undervalued compared to bitcoin and start their own bubble rises. Some alts will rise more in percentage terms than bitcoin with bigger relative gains. The alts having their own bubbles will pop first, followed by bitcoin.
so if that is what happens it would be good to sell alts nows buy bitcoin now then hope that btc doubles or goes up a nice bit and sell for profit and buy cheap alts then sell...
this would be nice profit if that turns out true