It even begs the question if those two instances of Extra Attack can be even combined. PHB says the Extra Attack features can not be combined. Which in the original sense only meant the amount of attacks but given the ability of making that cantrip attack is written into the Extra Attack feature...
Keep in mind the Warforged also has a Feat that further improves his AC and gets them some goodies depending on the core. Wonder what class might turn into the most durable tank with that. Only feels a tiny bit wasted on a Barb if you go for reckless, even if the gap between your normal AC and...
A big part of that question is: Does your party know this concept and is comfortable with it? Because the moment they attack the guy you CC'd or debuffed your pacifism approach went out of the window.
The Flanking rules nerf monsters with pack tactics, benefit parties with plenty front liners and punish those that have abilities generating otherwise quite rare advantage.
The moment you start to swarm your PCs with mooks that suddenly all have advantage might make em cry when random Milita Guy...
Advantage gets you something around ~3,3 and reduces you deviation by ~1 while it increases the odds of rolling your critical range too (4,75% if you only crit on a 20).
If you use the Eberron Warforged you get an insane amount of AC naturally anyway, yea. That should be no concern of your.
If you already stuck with Sword 'n Board, getting it higher won't hurt either though.
Ultimatly the question is: How much do you want to omptimize this character and how...
This. MC as Barb is only worth it if you don't expect to hit 20 anyway. Barbs just get IMHO the best Capstone of all classes.
4 ASIs on your primary Attributes that also break the natural 20 limitation AND interact with your core features? UNLIMITED USES OF YOUR CORE CLASS FEATURE?! THE VERY...
If it is more than 5 gods I simply stop bothering. I even prefer 1 or 3 to that.
Thing is, you can just give a single god more than one aspect and make him interesting, you don't have to split hairs and give names nobody even cares to remember anyway. If there are 20 gods I just strg+f the one...
Well, if that is the combo you want to go for, it would work.
The question is just: Do you want to heavily invest into that?
Two prone people are nice for some parties (Generally the more melee builds you have) but those parties rarely need a dedicated "tank" anyway. Keep in mind that prone...
IMHO both effects are rather weak to base any crunching around them.
The defensive one only grants you benefits if you campaign is quite deadly and people are expected to get dropped. This for example is rarely of concern in the campaigns I play in for people are generally good with the rules...
Most Groups and Campaigns don't even reach Tier 4 which makes it a softcap anyway. 20 is just a hard cap for it only makes sense to publish so much official material to be actually usefull. Creating classes with 30 levels in mind with not even 1% of player and customers even using those rules is...