Morning EMH was more valuable pre FP+. This year's current FP+ differs vastly from the FP+ version that was offered last April, and FP- that was offered prior to last year. So any posts talking about pre FP+ AM EMH may not be all that helpful.
Second, it also matter greatly which week. During busy weeks like Easter, EMH is still useful - both AM and PM. We've missed the last few Septembers, but our Sept hopping/AM EMH experience was vastly different from holiday week visits.. During September, a high overall percentage of total guests are onsite guests taking advantage of free dining. So mostly everyone has access to EMH's. Morning EMH was less useful. (though my experience was under FP-)
The other big takeaway I have learned...PLANNING to go to AM EMH is not the same as GOING to EMH. If you arrive at the EMH park AFTER EMH is over, then you arrive at a considerable DISADVANTAGE. Lots of times we thought we'd arrive for EMH, or stay until EMH, but missed the bus, overslept, or got tired early. On those days, we would have done much better at a non-EMH park. With new FP+ it is very hard to change your plans. Under old FP-, if it looked like we were going to miss AM EMH, we just swapped park days. If you swap park days now, you miss out on good FP options - AND maybe have to pay a penalty for changing your ADR! Yuck!
We almost always find PM EMH more useful, especially MK on a Sunday night. with new FP+, PM EMH has become MORE valuable. Guests leave in droves after they finish 3rd FP (maybe 4th FP at MK).
RE hopping: In short, hopping is much more valuable during busy weeks than slow weeks. Second, hopping to take advantage of peripheral hours is a plus, but hopping costs TIME. If you are only in the parks 8am-7pm - then hopping is usually a big LOSS of time.
One exception is hopping to get around FP tiering in HS and Epcot. In Epcot, guests are limited together TT or Soarin'. An early arrival +TT at RD+ hopping to HS to use your 3 FP (or the opposite to get on e-rides at HS) is great hopping.
Hopping from any park to MK mid-day, via WDW transportation often = a loss of an hour.