TL;DR; The VS2010 ISO is small because it excludes MSDN documentation, which is not yet available offline; users can access documentation online instead.

The reason is simple, it has no MSDN documentation in it. I for one never install the MSDN documentation and just use the online version and have always found it a pain to have it inside the same installation, but may people find it useful.
And, why is there no Offline MSDN documentation? The answer is simple, it is not ready yet…
Technorati Tags: ALM
If you've made it this far, it's worth connecting with our principal consultant and coach, Martin Hinshelwood, for a 30-minute 'ask me anything' call.
We partner with businesses across diverse industries, including finance, insurance, healthcare, pharmaceuticals, technology, engineering, transportation, hospitality, entertainment, legal, government, and military sectors.

Healthgrades

Emerson Process Management

Brandes Investment Partners L.P.

Flowmaster (a Mentor Graphics Company)

Hubtel Ghana

Akaditi

Genus Breeding Ltd

Capita Secure Information Solutions Ltd
NIT A/S

Big Data for Humans

Slicedbread

New Signature

Philips

DFDS

Illumina
Boxit Document Solutions

Alignment Healthcare

MacDonald Humfrey (Automation) Ltd.

Washington Department of Transport

Nottingham County Council

New Hampshire Supreme Court

Department of Work and Pensions (UK)

Royal Air Force

Washington Department of Enterprise Services

Jack Links

Boeing

New Signature

Healthgrades

Epic Games

Lockheed Martin