Is 1/2-inch collet capability important?

For anything beyond light trim work, yes. 1/2-inch shank bits are stiffer, run with less deflection, and are required for many larger profile bits. The top picks here all ship with both 1/4-inch and 1/2-inch collets; palm/compact routers like the Bosch Colt and DeWalt DWP611 are 1/4-inch only.