Ideal Beginner Triathlon

Well, it sort of depends on the athlete. A strong swimmer will not be as intimidated by a race with an ocean swim, but might find the bike or run really tough. My first tri had a pool swim, an easy two loop bike, and a one loop run. I chose that race for a few reasons, one of which was that it had a pool swim. 

If you were to look at a race without taking into account the beginner's background or ability, I'd think you would want: a) a swim that is not crowded, and with calm water, b) a bike course that is not crowded, with little or no turnarounds, and c) a run that is relatively flat with at least two aid stations. And, as a bonus, the race would have lots of fan support/music/etc.

Any triathlon with ocean swimming is not going to be beginner friendly. Swells and waves are not compatible with first timers.

If you have limited bike handling skills, then what seems "very technical" to you may not seem so technical to a more experienced rider.

How have you fallen off the bike? When stopping or when turning or what?

Well you're not that inexperienced then.  I've had problems dismounting at the line what with tired legs and all.  And I once fell over because I was climbing a steep, switch-backed road and took the inside line which was stupid steep.  I couldn't unclip in time after reaching 0 mph. :-)

I agree with your points about logistics, complexity, and "true beginners".  Ocean swim?  Not for "true beginners", nor are some of the complex urban courses.  I've seen "try a tri" sprint distance triathlons with calm lake swims, the bike as loop course on closed country roads, and the run on a pave trail.  That's beginner friendly.

There are "indoor triathlon" series, which in my opinion are the best for pure rookie triathletes, especially for the ones where the swim is an extremely daunting proposition.

Here are 2 separate series that are both well run - if you're lucky you'll have one in your area

http://indoortriathlonusa.com/

http://www.indoortri.com/

They have pool swims that are usually underweighted relative to the bike/run so even if you're a horrendous swimmer you won't affect your final result too much, bike is on a trainer so no bike handling problems, and the run is in an enclosed area. 

They're different than typical tris, in that usually its fixed time per swim/bike/run legs, so everyone finishes at the same time (they do multiple waves.)

Give it a go - even if you're completely green on the swim or bike, it's still a lot of fun. 

"Beginners" are the ones who show up at the race with an old mountain bike, beach cruiser, or 10 speed and tennis shoes...   They may still fall over, especially once they "graduate" from "beginner" status and start using fancy gear like clipless pedals.  (I know...I have...)

For me, an ideal "beginner triathlon" has enough room for inexperienced athletes to still be comfortable swimming, biking, and running and a Race Director who can limit the number of people in any "beginner wave" or even the AG waves to encourage beginners to participate.  An added touch is for the RD or local club to provide some on-site clinic/coaching for first timers to have a race strategy that makes them want to come back for a second, third, or 10th race.