OB1
Jedi Master
While I think the DMG could have done a little better in providing alternates to a 6-8 encounter day, I think as long as the daily xp guides are followed it's not that difficult to work around this. But I do think it's crucial that the daily xp number is hit regularly or players will have a tendency to walk over challenges because they are either not conserving resources or have too many to use. The following is off the top of my head and without the books near me, but I bet the community could quickly come up with some strong guidelines for 1 encounter, 2 encounter, and three encounter days.
6 Encounter Day - Med Encounter - Med Encounter - Short Rest - Hard Encounter - Easy Encounter - Short Rest - Easy Encounter - Deadly Encounter - Long Rest
3 Encounter Day - Hard Encounter - Short Rest - Deadly Encounter - Short Rest - Deadly Encounter - Long Rest
2 Encounter Day - Hard Encounter when reinforcements arrive it turns Deadly - Short Rest - Deadly Encounter - Long Rest
1 Encounter Day - Start Encounter with Hard group of Minions of the BBEG, when they are down to 2-3 minions Deadly BBEG enters the fight, when the board is cleared add a Hard group of 2-4 of the BBEG's top lieutenants seeking revenge - Long Rest
Regardless of the guidelines, I think it's important that the PCs can affect the outcome. There should be ways that the PCs can reduce an 8 encounter day to 3 encounters or prevent reinforcements from arriving in a 2 encounter day. It will make the day easier, and reduce the "challenge" of the fight, but that's because the players have done things to earn it.
And really, that's the same thing with optimized characters. Optimized PCs have spent resources that they could have spent on something else to reduce the randomness of combat encounters and make them "easier" to defeat. 5e actually encourages experimentation with character design because of the chosen level of appropriate design.
If the DM hands out magic items, it's a real bonus and combats will be easier. If players choose combat optimal designs for their characters, it's a real bonus and combats will be easier. In both cases, it opens up freedom to the DMs and Players to follow the path that it most enjoyable for them, rather than a preset design.
6 Encounter Day - Med Encounter - Med Encounter - Short Rest - Hard Encounter - Easy Encounter - Short Rest - Easy Encounter - Deadly Encounter - Long Rest
3 Encounter Day - Hard Encounter - Short Rest - Deadly Encounter - Short Rest - Deadly Encounter - Long Rest
2 Encounter Day - Hard Encounter when reinforcements arrive it turns Deadly - Short Rest - Deadly Encounter - Long Rest
1 Encounter Day - Start Encounter with Hard group of Minions of the BBEG, when they are down to 2-3 minions Deadly BBEG enters the fight, when the board is cleared add a Hard group of 2-4 of the BBEG's top lieutenants seeking revenge - Long Rest
Regardless of the guidelines, I think it's important that the PCs can affect the outcome. There should be ways that the PCs can reduce an 8 encounter day to 3 encounters or prevent reinforcements from arriving in a 2 encounter day. It will make the day easier, and reduce the "challenge" of the fight, but that's because the players have done things to earn it.
And really, that's the same thing with optimized characters. Optimized PCs have spent resources that they could have spent on something else to reduce the randomness of combat encounters and make them "easier" to defeat. 5e actually encourages experimentation with character design because of the chosen level of appropriate design.
If the DM hands out magic items, it's a real bonus and combats will be easier. If players choose combat optimal designs for their characters, it's a real bonus and combats will be easier. In both cases, it opens up freedom to the DMs and Players to follow the path that it most enjoyable for them, rather than a preset design.