Why is there no move to introduce regular versions of verb-forms as acceptable alternatives of irregular ones?
Solution 1:
The English language, like all languages, is not handed down from above, but rather exists in the minds of the people who speak it. Native speakers have no problems whatsoever learning the irregular verbs, and languages generally do not adapt to make themselves easier for non-native speakers.
What does happen is that if a large number of speakers, native or non-native, make similar mistakes, these mistakes may eventually become the norm. This does, in fact, happen with uncommonly used words. Erez Lieberman et al published a paper claiming that verbs have a quantifiable rate at which they become regularized:
a verb that is 100 times less frequent regularizes 10 times as fast.
However, this takes a long time and is not part of any kind of "effort" or managed process. It takes a significant effort to change the language of an entire people.
Consider the Chinese government's attempts to police the Chinese language(s) and to implement what is essentially spelling reform (technically: simplified characters). This is a huge effort, spanning decades, and requiring total re-education of a billion people. Yet the smaller dialects are not all dead and some are not even dying, the use of traditional Chinese characters has not completely died out, and the Chinese were starting with a population that had a high illiteracy rate. There is a huge cost involved in attempting this and most countries would simply be unable to carry it through.
Language is determined by its speakers. As long as most native people don't have problems with irregular forms, the language will continue to have them. Non-native speakers probably have as much chance of changing that as I do of getting China to ditch characters and go Pinyin all the time.
Also note that some verbs are being irregularized, see this Language Log post about "snuck".
Solution 2:
Your claim, that English irregular verbs are harder than French or German ones, is dubious.
For an English irregular verb, (except for to be), you only need to memorize three forms. For German irregular verbs, you need to know five different forms. For a French irregular verb, you may need to memorize eight or so different forms. Since French irregular verbs are three times as hard as English irregular verbs, one might expect there to be fewer of them.
Changing all irregular verbs to regular in any language is not going to be something you can do without a strong authoritarian government which the U.S., the U.K., Australia, and New Zealand don't currently have (and I hope they never will).
Solution 3:
"My question is: Why is there no move to introduce regular versions of verbs as acceptable alternatives of irregular ones? Could we even drop the irregular verbs all together?
Is it simply a case of tradition? Or is it impossible to forcibly manipulate a language- what has history taught us?"
Many attempts at "regularizing" English have failed (even Caxton and Webster kept irregularities so that they didn't change the language too much). If an authoritative enough source publishes a reform, then perhaps such changes might catch on. But what Mr. Shiny and New 安宇 says is correct: common usage can, eventually, win out over "technically correct" usage. In the meantime, you just have to go with what is currently "correct", by consulting a good dictionary in your "preferred" English (British or American).
Just look at Esperanto - a "global language" revolution: has that caught on?