While this would prevent lobby influence, if we have (hypothetically) a large population of uneducated people with the economic understanding of a twelve-year-old, then we basically have a group of twelve-year-olds voting. This would probably only be a problem in highly impoverished areas but a problem, none the less. It could easily be mitigated by policies, but that would clash with the whole "everyone votes" idea.
I think I might have to agree with you slightly. However, on the other hand you have a large group of informed youth that very rarely vote. In Australia only 40% of (relatively informed) youth voted, despite it being compulsory. In some cases, you actually need to give a people a kick in the backside, people that are actually informed but might be sitting in the political centre, or just unhappy with all major parties, to get them to vote.