Here in the US, photo ID isn't required to vote by mail either (at least in TX & NC). So really this only applies to people for whom getting to the DMV or the post office is a burden yet can take time off work on a Tuesday?
Probably beating a dead horse here, but just to be clear, in many (perhaps most) states, you can only vote by mail if you are not going to be in the state on voting day. Some states (Like Virginia) give exceptions for people who's jobs they consider essential (like doctors, police). Otherwise, legally speaking you have to go to a designated polling station during set hours on one day, regardless of whether you are working that day or not.
I agree that this may only be a small step towards increasing voter participation. But when I've read survey results for why people don't vote, the two biggest answers have been "I don't think my vote matters/will be counted" and "it's too much of a hassle to get to the polls on voting day"
Yes, that shows a certain amount of apathy and disenfranchisement on voters part, and it might very well explain why so many people believe they are not represented by the establishment.
A common refrain I hear about 'absentee ballots" (those sent in by mail) is that they are only considered when the vote total is very, very close. This might just be urban myth (and one perpetuated by "election night coverage" - where they only report vote totals from in-person voters, and declare the winner based on those results), but if people think an absentee ballot counts less than voting at an actual voting machine, it's a problem.
If your work day with commute is 8am to 6:30pm and your polling place is open from 7am-7pm, that's a problem. When there's an hour long line to vote and you have small children or inflexible appointments, that's a problem. When you are a student and you are told you can't vote in the location where you spend 9+ months of the year because somehow that isn't your 'place of residence,' that's a problem.