No. The changes in the monsters occur when:

You are in a party

• Monsters get +75% HP for every additional party member.¹

In a different difficulty level (Normal, Nightmare, Hell, Inferno)

These advanced enemies will have extra randomised abilities, including area of effect attacks, more ranged skills and area denial abilities designed to split up your team. On Hell and Inferno difficulties these creatures will get up to four extra special abilities, turning them into miniature bosses. Killing them will give you a chance to collect some of the best loot in the game.

Item drops improve with each difficulty mode, of course, but once you reach Inferno mode, top level items are divided into increasingly devastating tiers.

Source

This two are the only changes with monsters.

No. The changes in the monsters occur when:

You are in a party

• Monsters get +75% HP for every additional party member.¹

In a different difficulty level (Normal, Nightmare, Hell, Inferno)

These advanced enemies will have extra randomised abilities, including area of effect attacks, more ranged skills and area denial abilities designed to split up your team. On Hell and Inferno difficulties these creatures will get up to four extra special abilities, turning them into miniature bosses. Killing them will give you a chance to collect some of the best loot in the game.

Item drops improve with each difficulty mode, of course, but once you reach Inferno mode, top level items are divided into increasingly devastating tiers.

Source

This two are the only changes with monsters.