I'm pleased but a LITTLE disappointed. I hoped there would be more meddling enabled.
It seems diplomacy in any strategic game these days is completely meh. The game that showed me how unremarkable all the others were, was Gal Civ 2. Want to prop up factions by supplying them arms? Go ahead. Want to be a big scum bag and start wars and then sell arms to either side - sure.
I imagine why most games ignore this ability to meddle is 1) Its probably hard to code AI to handle it, let alone use it. And 2) It is easily unbalancing (i.e. easy to trick the AI). But FE is a SINGLE PLAYER GAME. For too long a game being single player has been perceived a flaw, when in reality it is an asset. If I hate an exploit, then I don't use it. If I find it fun to use and I still want a challenge, then I play on a harder difficulty. Balancing is much less critical. Look at Skyrim. If I really want a sword that will kill anything I touch, then I can make one in the Construction kit in 5 min - the point is again - there are more opportunities for fun mechanics since everything doesn't have to be balanced to the exact nanometer.
So I was hoping a FE expansion would introduce the ability to meddle. Off the top of my head, you could cast spells that would remove the fog of war from discovered areas - Scrying. Seeing the collection of nations at war in realtime is much more exciting than seeing nothing outside of my borders. Perhaps you can build mercenaries and sell or give these to other nations. Yes, you can presently give them more liquid aid, but seeing a bunch of money disappear is a lot different than seeing units that I provide turn the tide of a war. Maybe I can take some of these mercenaries and disguise them as bandits. They would have some weakness as opposed to regular units (perhaps smaller stack size, and a chance of discovery if they every lose a battle), but then I can secretly wreck havoc on nations (even friends) without having to declare war.
But there is no reason I couldn't also meddle through magic. Maybe there is a spell that lets me cast another spell normally limited to my realm anywhere in the world. Maybe there is only a small chance of telling who casts it, but then I could be completely neutral and through a well placed spell stop a larger nation from swallowing up a weaker one.
Maybe I can cast "Capture" on the strategic map which when cast on a monster and that monster is slain within one turn allows me to hold it in a magical prison. Why? Because then I can cast Release which will drop the monster anywhere I wish at full health. Maybe there is an improved version of the spell that allows me to take full control of the monster as it goes on its merry rampage. Maybe I can cast confuse anywhere in the world on an army and take control of that army for a tiny number of turns. All of this can be balanced by costs and conditions, and as I said before the balance doesn't have to be exact. As long as its fun - and darn it, meddling is FUN.