I think Flexible mode with 2.5ms frame size could help, but not reach as good results as ePTP.
Sure latency is way better than actual 802.11n-based TDD mode in ePMP 1000/2000, but I think you can do more.
We, as WISP, are continuously competing with fiber-based competitors with very low latency.
Having a link with 2-7ms latency instead of 1-2ms means a lot for some customers.
And what about when you have two hops? You're adding about 10ms of latency or more!
You say Force 300 is an upgrade, a "step forward", but you have to think about all situations. You have to admit ePTP mode was helpfull when it was launched on ePMP 1000 and it's even more usefull now the market is changed and every millisecond counts.
ePTP Mode is very, very helpfull when you need low-latency and low-budget links. We used and we're using it A LOT, and, as I can see from this thread, we're not alone.
You can see below the difference from Force 200 ePTP Mode in two very clean links.
Force 200 link is 95.5% traffic on MCS15 (64 QAM 5/6), Force 300 link is 95.6% traffic on DS MCS 9 (256 QAM 5/6), so very clean, both on 20MHz channel.
Both links were not under load.
As you can see ePTP is far more stable and the latency is very low. On Force 300 the latency is 4ms as avg, which is 4x times the latency on ePTP.
How can you say ePTP is "unnecessary"? That's a step backwards, not a step forward!
Force 200 ePTP Mode
Force 300 PTP Mode