All side bay side readings I have seen show 4e either matched or beat the amount of real information about creatures in earlier editions I have no idea tbh.
The 2e Monstrous Manual did things that the 4e one didn't. For example here's the 2e section on goblins.
Habitat/Society: Humans would consider the caves and underground dwellings of goblins to be dank and dismal. Those few tribes that live above ground are found in ruins, and are only active at night or on very dark, cloudy days. They use no form of sanitation, and their lairs have a foul stench. Goblins seem to be somewhat resistant to the diseases that breed in such filth.
They live a communal life, sharing large common areas for eating and sleeping. Only leaders have separate living spaces. All their possessions are carried with them. Property of the tribe is kept with the chief and sub-chiefs. Most of their goods are stolen, although they do manufacture their own garments and leather goods. The concept of privacy is largely foreign to goblins.
A typical goblin tribe has 40-400 (4d10 x 10) adult male warriors. For every 40 goblins there will be a leader and his 4 assistants, each having 1 Hit Die (7 hit points). For every 200 goblins there will be a sub-chief and 2-8 (2d4) bodyguards, each of which has 1+1 Hit Dice (8 hit points), is Armor Class 5, and armed with a battle axe. The tribe has a single goblin chief and 2-8 (2d4) bodyguards each of 2 Hit Dice, Armor Class 4, and armed with two weapons.
There is a 25% chance that 10% of their force will be mounted upon huge
worgs, and have another 10-40 (1d4x10) unmounted worgs with them. There is a 60% chance that the lair is guarded by 5-30 (5d6) such wolves, and a 20% chance of 2-12 (2d6)
bugbears. Goblin shamans are rare, but have been known to reach 7th level. Their spheres include: Divination, Healing (reversed), Protection, and Sun (reversed).
In addition to the males, there will be adult females equal to 60% of their number and children equal to the total number of adults in the lair. Neither will fight in battles.
A goblin tribe has an exact pecking order; each member knows who is above him and who is below him. They fight amongst themselves constantly to move up this social ladder.
They often take slaves for both food and labor. The tribe will have slaves of several races numbering 10-40% of the size of the tribe. Slaves are always kept shackled, and are staked to a common chain when sleeping.
Goblins hate most other humanoids, gnomes and dwarves in particular, and work to exterminate them whenever possible.
Ecology: Goblins live only 50 years or so. They do not need to eat much, but will kill just for the pleasure of it. They eat any creature from rats and snakes to humans. In lean times they will eat carrion. Goblins usually spoil their habitat, driving game from it and depleting the area of all resources. They are decent miners, able to note new or unusual construction in an underground area 25% of the time, and any habitat will soon be expanded by a maze-like network of tunnels.
Now I consider most of that to be aggressively bad in many ways; for example it only talks about a typical goblin tribe and makes all goblins tribal and claims all goblins use no sanitation. It's ... stereotypical. But it also does some very significant things that I don't think any other MM actually does.