Frenzy is very viable on the Seasonal realm. I killed Uber Lilith with a Frenzy build. Used The Barber + Berserk Ripping for that build. Very strong, especially with +3 brawling skill ranks on your amulet and +4 ranks of Kick on your pants. Use Frenzy for your main damage, keep Berserking up as much as possible. Use Kick with the talent that makes it consume all your fury. Then grab the passive that gives you +3 seconds of berserking when you use a brawling skill (Kick is one of those skills). Use Butcher’s Cleaver + Ramaladni’s dual-wield, and you want the +50% attack speed aspect on 2h slashing weapon (sword is ideal).
Don’t use Battle Trance unique amulet – it’s a noob trap since the primary property on it is +attack speed for NON-FRENZY skills, and since Kick is your only other damage ability in this build besides Frenzy, and since Kick is a cooldown skill, the Battle Trance unique is literally a useless item for this build. On top of that, the amount of damage scaling per rank of Frenzy is much less than that of other Core skills (Frenzy is a basic skill and they get less +damage per additional rank compared to Core skills), making the +3 ranks of Frenzy on the amulet amount to a very small damage increase. In exchange, you have to give up 30% damage on your amulet from the lack of Edgemaster’s aspect (30% [x] more damage when your fury is full – which is so often is in this Frenzy build).
Wrath Glyph is very important in this build too, for fortify and fury generation. Frenzy generates 7 fury baseline at max stacks (4+3), and Wrath Glyph adds 3 more fury on crits (with 40% crit chance this is worth roughly 1.2 Fury per Frenzy attack on average). So we can say Frenzy generates about 8.2 fury per hit on average, before calculating additional resource generation like the 1.56x increase from your shout, or the usually 15-20% from willpower, and another roughly 20-36% possible from +res gen rolls on both of your rings. This means when you dump your fury with Kick, because of your high base fury generation with Frenzy plus the crazy attack speed of it, you are back to full fury very fast.
For your ultimate, I would use wrath of the berserker for another source of berserking, since if you’re not berserking you’re not able to apply bleeds from berserk ripping, which is where all your real damage comes from. So you want to use your shouts, wrath of the berserker, and Kick, to keep up berserking at all times if possible. Smart rotation between these abilities, plus getting lucky with Disembowel procs, means you can be in a state of berserking almost all of the time you’re in combat, giving you access to your full damage almost all the time. I love this build for the minimal downtime, and because kick makes stuff vulnerable, which really helps pump huge damage into bosses and elites.
Speaking of berserking, two of the best things you can do is get +berserking duration on your boots and amulet. You can also get it on pants, but you need DR while Fort, Total Armor, and DR from Close, leaving you room for only one last 4th stat. You’d be picking between +4 ranks of Kick or +30% berserking duration. It’s better to get +ranks of Kick on pants since it lowers the cooldown on your Kick ability, which is how you apply vulnerable if mobs don’t die within the 3-second Exploit glyph window.
You can get up to 31.5% duration to berserking on one roll on your boots. That makes your 3 second berserking duration after using kick turn into a 4 second berserking! 1 extra second of berserking uptime from Kick is 1 less second of downtime with no berserking before your shouts come back up or your next charge of Kick has cooled down. This is very important to the build too so wanted to mention it!
Enjoy!