Heliamphora is very species specific and beyond that, very individual specific.
I have several crosses that were all done at the same time. Some hybrid populations are still all small and immature.
Other crosses have specimens that became adults in under two years, while some siblings took a little longer, and some have yet to mature.
This is true even though they have all been grown under the exact same conditions, and in the case of siblings, the same pot.
So, in my experience, hybrid vigor does exist, but it's very individualized.
This is one reason for selecting and naming a special cultivar, wink wink ;-)
I would also assume the inverse is true as well, some are destined to be runts...
I don't have any experience making Nepenthes hybrids, so I don't know if this is true of them... but I would have to assume so.