Spend time wisely
First, a general note is important. The strategic problem with judo throws for BJJ is that they require a major time investment to learn, and the payoff in BJJ competition is low. According to the BJJ rules, you can drop right to the ground and avoid situations where throwing is practical.
With that in mind, we'll look at your three situations.
I go for the throw and I get taken down instead
In order for throws to work, you need to practice them to competence. This is no different from shooting a single leg takedown but being sprawled on. Every attack (strike, throw, takedown, etc.) can be blocked/countered. Judo is built around being able to execute throws fast/efficiently enough that those counter movements create other openings, which brings us to your second point.
I go for the throw but I am forced to do a takedown/sweep instead because of their posture
What's wrong with this? If the threat of a throw provides an opening to otherwise attain a superior position, then just take it. There is always some kind of opening; the difficulty is when the opening becomes illegal under whatever ruleset you are using.
I am able to pull off the throw but they land in a strange way that further limits my ability to attack them
Throw with real control
The ideal judo training throw looks something like this seoi nage (shoulder throw). There are four elements that are nominally considered for scoring in competition:
- uke falling largely on the back
A further element that is demonstrated in the video but not considered for judo competition scoring is the finishing position. In judo competition, you can roll through to roll uke across their back and score an ippon to end the match, but this is not useful in the BJJ setting because throws don't end the match, and you end up in an inferior position. In this demonstration, tori finishes in a standing position where
- Uke's fall is supported and they are not dropped on their spine
- Uke's legs are already passed
- Tori has structure to prevent uke from being able to pull them down to the ground after the throw
- Tori can continue to groundwork if desired, with the obvious continuation being a juji gatame (cross body armlock).
- In a self-defense situation, tori would be able to disengage at this point, or stomp on the grounded opponent.