Seed pods generally do not prevent next year's blooms, but the plant builds strenght while photosynthesizing after flowering. If you deadhead, the plant tend to be more prolific in creating offsets (bulblets) and thus you will get larger groups more quickly, and you direct energy into bulb enlargement. So if you have a relatively small immature bulb, deadheading after flowering can give good result. However, even if you do not, it should not affect next year's blooms.

Thanks Ken, my crosses will not be in vain!