There are a few misconceptions regarding these matters, at least as i see it.
Lower weight classes offer different kinds of fights and display different qualities. They are providing amazing fights, but this is related to the fighters not the weight or speed alone.
Speed is often mistaken for skill. Skill isn't tied to speed or size.
There are also the expectations from HW fighters to be fast and durable like the lower weight class fighters while retaining their power. You can't have everything. Even the best cardio-machine at HW will not be able to fight another human being for the same amount of time as a lower weight athlete. Are there exceptions? Yes, probably. Should HWs be judged so harshly and sometimes unreasonably based on the few exceptions, especially in a demanding combat sport like MMA? No, in my opinion at least.
Lower weight classes offer different kinds of fights and display different qualities. They are providing amazing fights, but this is related to the fighters not the weight or speed alone.
Speed is often mistaken for skill. Skill isn't tied to speed or size.
There are also the expectations from HW fighters to be fast and durable like the lower weight class fighters while retaining their power. You can't have everything. Even the best cardio-machine at HW will not be able to fight another human being for the same amount of time as a lower weight athlete. Are there exceptions? Yes, probably. Should HWs be judged so harshly and sometimes unreasonably based on the few exceptions, especially in a demanding combat sport like MMA? No, in my opinion at least.