Point of reference; I'm the son and grandson of professional mechanics.
I've been working on motors and vehicles for about 50 yrs. I've been riding for 45+ yrs.
First question, according to this site: http://www.zeroto60times.com/vehicle-make/zero-0-60-mph-times/ the electric motorcycles seem to have performance pretty comparable to current gasoline motorcycles. I see 0 to 60 times as low as 3.3 seconds - which isn't as fast as the fastest racing bikes, but it's pretty respectable.
Electric vehicles can make full power at any RPM. Gas engines make peak HP and torque at two different RPMs. 0-60 is mostly power to weight ratio. 3.3 seconds is very respectable.
Second question - is it accurate to say that older air cooled bikes are both less fuel efficient and have a lower power to weight ratio than a more modern bike?
There are a few new air cooled engines - mostly cruisers, which aren't made for max performance or mpgs. The bigger factor is electronic ignition and fuel injection. It compensates for a wide variety of variables making it WAY more efficient - and actually lower maintenance.
Third question - in terms of a bike, I'm looking for something that I won't need to work on to keep running. Also a big fan of ABS and EFI here. My experience with cars is that older vehicles require more maintenance and repairs than newer vehicles - is this not true for motorcycles as well?
I will never go back to carburetors. EFI includes electronic ignition.
Maintenance on my bikes (an 07 and 09); oil, spark plugs, air filter. Lube, adjust chain (easy), replace chain & sprockets about 20K miles (fairly easy but needs special socket for front sprocket), adj. belt (once a yr). Tires - I buy tires online, remove the wheel and take them to a friend or dealer. Fuel stabilizer and charge batts in winter - I'm in Wisc.
All bikes should have the valve clearances checked once (unless it has a LOT of miles). I've done it on three bikes, had dealer do one.
I'm not trying to go the minimum cost route here. Money isn't a huge constraint, although I'm not going to spend 16K on a bike regardless of whether it's electric or gasoline powered. Mostly, I just want to learn to become a good rider. So... fourth question. For a cost effective commute in the city, doesn't a scooter provide a better option than a motorcycle? Automatic transmission, cargo under the seat, comfortable seating position, etc.?
I started thinking about a scooter and various factors led me to the motorcycle option. (I've got the motorcycle course this weekend. First new thing I've tried in quite a while, so I'm pretty excited!)
'Effective' and 'comfort' are relative and personal opinion elements.
There are a few motorcycle-scooter hybrids, sometimes called super-scooters. Burgman is probably the most common, made by Suzuki, up to 650cc. Honda makes a couple - some are more MCish and some are more scooterish.
Both of my bikes have saddle bags - factory on one, aftermarket on other. I also have tank bags and tail bags, but they're not always on the bike.
I always recommend a used bike for your first, assume you will drop it - less body work is better. Smaller is generally better, unless you want to go on the highways.
Also; I don't mind riding in the rain, I have the gear for it. But, I do NOT commute in the rain if I know about it, because - car drivers do not expect bikes on the road then so they don't even see you. I'd rather drive thru miles of construction.