As stated before, to maximize or to not maximize depends almost entirely on your situation. For many of these Pokémon, maximizing HP also maximizes defensive capabilities, while having one point less can sometimes produce the same type of problems as mentioned when you maximize a base 70 Pokémon’s HP (For instance, a Deoxys-D with 303 HP takes 37 damage from Stealth Rock, and two rounds of leftovers recovery won’t completely heal it). However, as appealing as maximizing Leftovers recovery sounds, sandstorm and hail negate this advantage, and leaves your Pokémon suffering from increased indirect damage. If you have one of these weathers in your team, it is generally a bad idea to maximize the HP EVs of these Pokémon unless they are immune to it. However, when you do not have damaging weather on your side, it can go both ways. Do you wish to maximize the HP EVs of one of these Pokémon due to your own team, or do you maximize HP based on the possibility of sandstorm or hail? You should consider the frequency of these weathers in different metagames. For example, sandstorm is common in OU due to Hippowdon’s and Tyranitar’s presence, but it is quite rare in Ubers due to Kyogre and Groudon being everywhere, canceling out the sandstorm Tyranitar creates, or the hail Abomasnow brings. Therefore, it is safer to maximize HP of any of these Pokémon in the Uber metagame compared to the OU metagame. Also consider other factors such as Rapid Spin or Taunt that could prevent the set up on entry hazards. It would probably be a more preferable option to max HP when you have these and no damaging weather on your side (that hurts it obviously).