Many people want GoldenDict to combine 3 functionalities: dictionary, flashcard program (to learn words) and program for creating own dictionaries.
I suggest not to distract attention of creators of GoldenDict from developing dictionary, because the other 2 functionalities (learning words and creating dictionaries) can already be very well implemented by using Anki (
www.ichi2.net/anki). It's free, open source and can work under several operating systems.
It's the most convenient program for creating dictionaries. First you create dictionary and then enter information in fields of your choice (word, translation, meaning, synonyms, antonyms, transcription, image, audio, video etc.). So you work with fields and do not see tags. Anki supports formatting - it has what-you-see-is-what-you-get editor, you can even use html formatting. Anki uses Unicode (dictionary can be for any languages). You can even create multilingual concept dictionaries. Anki dictionaries are based on sqlite database (if I'm not mistaken).
By using the main functionality of Anki - learning words - you can even learn new words in your dictionary.
The only problem is that GoldenDict cannot look up words in dictionaries of Anki format. I believe it is easier to solve this problem than to try to create monster program combining the 3 functionalities and to compete with the best in the world flashcard program Anki.
Till this problem is solved, you can use Anki to create your dictionary. When it is ready, you can extract it into .txt format, convert this file to .dsl format and use it as dictionary with GoldenDict. Or just to look up words in 2 programs - GoldenDict and Anki.