As CN Tower provides it's benefit in puppet cites too, I don't understand why it belongs in the "worst wonders" category.
As a wonder, the CN tower is great.
But it comes WAY to late - like all the stuff from Telecommunication. Or to be exact: Telecommunications is situated in a way to poor spot to make early research viable. Penicilin isn't actually a great tech (at least imho), and ecology is very situational (either no aluminium or many desert cities). Maybe you will push for Atomic theory tocheck if you have uranium, but usually Satellites will be the most relevant tech you want to grab.
As for the Telecommunication benefits:
Nuclear subs will rarely make a difference at that point of the tech tree. But hey, better than nothing (like the old ecology 90% of the time).
If there was any kind of war, nuclear action has already occured, so the
bomb shelter could only help to salvage what is left. WAY to late, imho it should be moved to Nuclear Fission, and Telecommunications should get some sort of SDI-like national wonder. THAT would make the tech worthwhile.
The
CN Tower pop point is neat, but happiness should not be an issue at that point, and the free broadcast towers come WAY to late. If you played for culture victory you should have hardbuild them instantly after you researched radio, if you play for anything else you don't need them anymore. If the Eiffel Tower (or a similiar wonder at that point) would give free broadcast towers (maybe to the 4 biggest cities only), that would be good. But the CN tower at this point of the game? Meh.
Personally I would change him like that:
CN Tower
+2
and
in all cities, free broadcast tower in all cities, +10%
,
,
from all broadcast towers.