If you look around you can find some freeware replacement .air files and other aircraft cfg modifications that supposedly improve the flight dynamics of some of the aircraft for fs2004.
Can't say that they actually DO... 'cause I've never really PILOTED a 747 or A320 or anything like that

.
The freeware Real Air Simulations C172 supposedly flies far more realistically than the MS stock ones.... and I have it installed. And it is certainly noticeably different in flight characteristics.
Some of the "emergency stuff" is available in the payware ALERT software including complex multi-system interactive and progressive failures.
As to the price of an "upgraded" more realistic sim being offered from Microsoft.......
I wonder how many of us are already using a significant amount of payware that is bringing MS's effort closer to "as real as it gets"? When you add in the cost of all those paid add ons to the price of the original program....... Microsoft might be "missing the boat" a bit

. If they offered all those options themselves ... they'd get the whole piece of the pie instead of just a slice of it. Add only a couple of payware scenery and aircraft and such.... and the total price is easily
well over $100.
But .....countering my own suggestion...... my guess is that those of us who are looking for more realism in this stuff are a
VERY tiny minority out of the vast number of more casual users.... who would really balk at the higher price tag and would likely hate the difficult to learn and fly product.
So..... if you want significant realism... likely you'll have to continue to modify the product with freeware and payware to get what you want even in future MS releases. This program is, after all, a mass market product sold to make money.
I think there are commercial FAA approved products already available if you REALLY want realism. But the pricetag for them is as
HIGH as you would expect for a niche' market product.
best,
................john