I mean if you could make your character concepts without it costing you mechanical effectiveness, would you be offended or angry or whatever at 5E? I don't think you would. You could continue to play how you always have, so why not try to allow the other play styles into the game?
Specify what you mean by "Defender Wizard", considering the role of "defender" doesn't actually exist outside the design scope of 4E.
As for the fighter, yes, you can absolutely make that character. Put your highest stats in Dex, Str and Charisma. Wear light armour. Wield a heavy weapon. Choose a Background that gives you social skills. Pick a feat that makes you better at heavy weapons. Boom. It's that easy.
If you're going to say your character is not as good at heavy weapons as someone who put more points in strength, well, they're also not as mobile and nible as you, and don't have the kind of social skills you do. You're giving up some (minor) specialisation for a broader scope of abilities. You're going to be just 1 or 2 points behind the specialised guy anyway.
When 4E was released, there was no druid, monk, psion, or bard. There was no swordmage. You couldn't make them. Is this a failing of 4E? No. Because the system expanded to address these issues eventually, as 5E will undoubtedly do, as well.
For other classes sure. It might be a little unrealistic, but a Fighter is supposed to be best at combat and it accomplishes that through the use of weapons and armor.
It should be able to use any combination of those effectively.
See above. Conan the Barbarian had no armor and used a two-handed sword. You'll note that he did not 'rage' and was exceptionally skilled having come out of the gladiatorial pits. So he wasn't an actual barbarian class, he was a barbarian as a sub-race to human.
(All of the write-ups I've ever seen have him something like 18/17-18/18/12-15/11-15/14-17 - - http://old.enworld.org/Inzeladun/conan.htm , http://forum.rpg.net/showthread.php?622972-4e-Conan-the-Barbarian-NPC , or the stats from the old D&D module are in the middle of http://dragonsfoot.org/forums/viewtopic.php?f=11&t=60964&hilit=conan+stats&start=60 ).
Have fun with your game before 5E gets shelved because it could not bring in enough income.![]()
While this was supposed to be a snappy parting shot, it frankly puts everything you've ever posted into its proper perspective.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.