Economy in ultimate edition, help needed

The change was deliberate to slow down the colony rush.  You now need to build up your population quickly on the newly colonized planets to change them from economic drains to productive colonies.  Things you can try are to select economic ability bonuses when choosing your race, choose the Federalist party for its economic bonus, grab any economic resources that you can, and don't set your tax rate too high (perhaps counterintuitive, but the higher approval from lower tax rates helps to build up the population more quickly).

You might also consider using colony ships with more colony modules-a late version of DA downsized the colony module from DL's 500M pop to 250M, and since growth is based on population, this means less growth, which causes your colonies to take more time before they break even.

Engines of course also cost more in DA/TA, and that might be one reason you're spending more than you're used to, particularly if you're rush buying your ships.  Until you get a feel for it, keep your leases to a minimum, and don't outright rush buy things, either.  One viable method is to use base hulls (tiny or small, with sufficient miniaturization) and a single colony module-it results in a much cheaper colony ship, compared to doing the same trick in DL.

Additionally, morale is a little harder in DA/TA than it is in DL, and in fact if you're playing a non-Terran/Minor Race tech tree in TA, the early game can be considerably tougher, morale-wise, although by late game you ought to have more than enough.

Since these are things involving the base code of the game, no mod would be able to cause a direct change, but presumably if you monkeyed around with morale and income (and potentially population growth) boosters enough you could achieve your desired result.

Hope that helps, but it's hard to offer much without you being more specific in the problems you're having.

To Publius of NV's point, the relation between morale and population growth on each individual planet has the following "steps":

1) Morale at 100%: boost to population growth. In the case of races with the super breeder ability, the boost is even considerably higher

2) Morale 76% or higher: slight boost to population growth

3) Morale 46% or less: decrease in population growth

4) Morale 26% (not entirely sure of the exact number) or lower: no population growth

Therefore, at the start of the game keep your approval at 100% (or 76% if 100% is not possible). My own rule of thumb is that I'll look into raising taxes and reducing approval once my cash can only cover about 40 weeks at my current spending.

Some of the basic technologies that improve economy, morale or population growth will help a great deal. Try also to get some of these technologies through trading with the AI, especially if they have some cheap unique techs that you couldn't research yourself. Offer them 999 influence points plus some technology of your own in return. Minor races make great trading partners since it's less risky to give them a leg up compared to giving technology to major races that may at some point use it against you.

Consider only colonizing planets of a decent planet quality (in small/tiny galaxies you may want to colonize almost any planet whereas as of large galaxies you could ignore the ones below PQ7). Also, at first only develop your homeworld and about 2 other planets. Colonize the others but do not build on them until your economy is getting stronger or until the population on those planets has become high enough to warrant building economic buildings (e.g. banks)

Slight correction to Noctilucus's numbers:

100% = 2x (8x if Super Breeder)
76-99% = 1.25x (25% more)
41-75% = normal growth, 1x
20-40% = no growth
0%-19% = 10% population loss (I think, I've forgotten) per turn

Well, it sucks that mods can't change it. Oh well, I guess I'll just learn to deal with it. Thanks for all the answers guys.