Boarding procedures are planned by the airline contract staff, and not up to SQ to decide how to board.

Food: SQ at least tried to give you an alternate choice .. as you said, with an apology. If you took another airline, say, AA, they'll just say sorry, your choice is, take it or leave it.

Drinks: Budweiser is the only option cos teh flight originated from the US and that is only what is boarded as a 'local' beer. If you had told the staff that you are 'allergic' to Bud, then maybe they might have sourced out something else but if its all due to taste, then sorry, that's it. The 1/4 fill of glass is due to safety reasons. If they fill it up to even half, in SQ's experience, may cause spillage when turbulence occurs. If you want more, then just tell them to top it more. They are not rationing, trust me.

But overall, SQ even in economy class, will go out of their way to please you. Hot towels, immediate answering of call button. I was rather pleased with them when I flew them in economy a few months back after an absence of over 10 years (of flying SQ coach). Abeit in the A380, I was still surprised with the level of service one got. Even befriended a FA and we're still writing each other on Facebook !