I don't like the idea of Warhorns because they're going to be immersion-breakers for me. They're not well thought out and integrated with the setting they've created.
For example, 3PV drones are the perfect example of how much they cared for consistency in their game. It solves both a gameplay and an immersion problem at the same time, while fitting into a Battletech setting.
Warhorns, not much. It's like they didn't sit down and think "Ok, if Clans really used these things in BT, what would they play?". The obvious choices would probably the be the sounds of the animals of the Clans they were fighting for. This would be more immersive and reinforce the idea of people actually fighting for their clans. What do we have instead? Just a bunch of random sounds you'd expect in a "teenage" game like LoL, or like someone else in this thread said "Sounds you'd expect to hear in an Arcade."
Forcing these on players will annoy some purely because of the way they sound, and annoy some purely because they're immersion-breakers.
It'd have been best if they just played the sound where it belongs, in cockpit. Heavy Metal gets a free-ticket because it's unique in a sense that it exists in lore, has external speakers and is extremely rare on the battlefield.
If they really want people to show off their "swag", then give the option to disable these Warhorn sounds for those who don't want to hear this BS.
Even though exaggerated, I think this video sums up what we're in for:
They could definitely be creative with these and come up with stuff that doesn't break the immersion.