It is depressing to see that the many reports of issues have gone unnoticed. I'd gladly write some concise suggestions for how to improve the available tools and the /mods/ folder, but let's look at the process shall we?
Step 1. Make reports.
Step 2. Most of it doesn't get read.
Step 3. Devs only look for bite-sized bits with "a lot of impact".
Step 4. Then they get put on a list and forwarded for a "maybe".
Step 5. A few months, half a year later, a percent of the issues gets fixed.
Step 6. This thread.
Now what's the point of repeating ourselves? Step 1 isn't that appealing considering the process.
Then don't.
To set expectations: Assume that the modding won't improve at all. That way, if it does, hooray. 
I said what has to be done. We did that with "Name 5 things you'd like to see fixed in FE 1.3" and the consensus 5 things got addressed.
The problem is that people will make an unpriortized lists of hundreds of things that they want, most of which aren't realistic. And yes, they get ignored because there's only so much time available.
If the modding community could put together a VERY short list (like 5 things) they think would make a big difference but wouldn't require massive effort to implement, they're likely to get done.
And it has to be specific.
For example:
2. Not all xml is handled equally. for example, you cannot put a calculation in the experience point bonus that a city gives a unit. But you can put a calculation in the bonuses a building gives trained units.
That's not specific enough. The XML will never be "handled equally". That would be a massive undertaking. My suggestion would be to explain what you are looking to do so we can help accomodate that.
Let me give you my own personal requests:
1. Let the player choose MODS where it works as following:
* In the mods folder, each sub-directory that has an elementaldefs.xml would count as a mod and the user could pick.
* Elementaldefs.xml should have an option to disable the following things in it:
a. The base city improvements (so only improvements in this directory will be seen)
b. The base player technologies (so only technologies in this directory will be able to be seen)
c. the base magic spells (...)
2. Any improvement/tech/gameitem that has a duplicate internal ID to what is in the base directory should be ovewritten by the mod.
3. The map editor needs to be able to load up tactical battle maps over and over without losing special tile modifiers (this is a bug0
4. The ability to create random map stamps should be spelled out to the player such that it explains in the dialog what the player does to create a map stamp.
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That is what I mean by specific. Now, in LH, scenarios are much easier to create because the problems I mentioned above had to be dealt with.