I'll address your points one by one
Dynamic MMR - to clarify, dynamic MMR is the one where your rank decays if you don't play, or is it the one where people of different MMR can queue together and... magic happens?
Starting rating - I agree it'd be beneficial to have rating start higher. Maybe not as high as 1500, but something close to 1000 (lower or higher or exactly 1000) would be pretty alright.
BG and arena queue announcer for sure, it's easy to implement. If we have enough BGs going on, that'll be disabled but the arena one is definitely a plus (unless we have like 30 teams queuing at the same time lols)
3v3 Incentives - I did mention someone in one of my posts (Reddit perhaps?) that we're planning on adding systems not present in "vanilla" Wrath of the Lich King, and adding incentives for PvP (especially arenas) is one of them. PvP (and especially arena) was pretty much a second-class citizen compared to other parts of the game during WOTLK, partly because it was still in its rather early stages. The PVE rewards in WOTLK are vastly better and worth working for than what PVP has to offer. I have plans to implement some manner of rewards system that would be updated each season to stay fresh. Luckily, Omega Season one starts around mid-February, so there's still time to cement the ideas I've been throwing around. I had a similar system planned and introduced late into Omega 2.0's life cycle, and there's good ideas to re-use from there.
GENERAL SERVER PROMOTION
Videos - They're coming. More info on that soon.
Armory and ladders - Hasn't been discussed yet as we've been focusing on bigger fish, but it shouldn't be too hard to implement. It's worth mentioning it might take longer to implement if we want to have both those features working nice and smooth, lacking the usual bugs they usually sport.
Anti-cheating and anti-scripting protection - We've got protection stuff, but it's worth noting no matter how many layers of Wardens or Cortanas you have in place, there's always going to be some stupid hack that bypasses them. WOTLK is ten years old, and with its age come flaws in its code. I think we'll be just fine with what we've currently got installed, but if you ever think someone is cheating, remember to take lots of screenshots and have timestamped chat boxes!
And yeah, I think the rates are good. Here's the reasoning behind each:
3X XP - WOTLK is 10 years old, people are sick of leveling through the same stuff all the time. 3X seems balanced enough that leveling is fast but not too fast. That and the option of double XP through Recruit-a-Friend should give players who want to level even faster an alternative option (as long as they can find a friend!)
2X Rep - Honestly, even 1X rep is fast enough for me, personally. However, it's once again content people have done for 10 years. While 3X is excessive, 2X should land in that sweet spot where you have to work for it, but not to the level of stupid increments that WOD/Legion/BFA has with their world quest-based reputation.
2X Honor - Honor at 1x is fine. Honor at 3X is too much, and people have to much of it to spare there's zillions of epic gems available once they hit the vendors. 2X seems alright in terms of not forcing you to go through more battlegrounds than you have to in order to get geared up.
3X WORLD DROP (chance, not amount) - We had 3X drop to the amount, and it was overly sufficient to say the least. It yielded more gold (which made the economy a bit wonkier than it should) and it made everyone take more tiring trips to vendor their full bags. This time around we decided to set the drop amount to the usual 1x, but increase the chances of items dropping. So, a Damaged Necklace or Book of Glyph Mastery has, say, a 1% chance to drop. With triple the drop rate, it now has a 3% chance to drop. Same goes for BOE rares and epics. Makes grinding out in the world feel better without showering the player with trash.