The word Heresy comes from the a greek root that means "choice". The essense of Heresy is chosing something different than that which has been delivered.
There were things in the early Church recognized as Heresies that were not only issues of Jesus Divinity.
Some examples include the Montanists, the Donatists, and Pelagianism.
None of these denied God, or Christ, but were all considered Heresies because they chose to follow their own ideas rather than those that were delivered by God through his word, and his Church.
I would like to make a note of historical accuracy. Tyndale is often said to have been declared heretical simply for translating the bible into English. He is also often said to have been martyred by the Catholic Church.
In point of fact, the issue was not simply that Tyndale translated the bible from Latin into English. There had already been translators who had worked on translating the bible into the common languages with the approval of the Church.
The issue was that Tyndale was denied permission by the Church to translate the bible because he was using his translation to advance his own doctrinal views in opposition to the teachings of the Catholic Church. Tyndale had been involved in controversy and had been accused of Heresy before he ever began his translation.
Some examples were that Tyndale used the literal translation of clergy office positions rather than the transliterated terms (he used elder rather than priest, and overseer rather than bishop) he also used the word "congregation" rather than Church.
On the one hand these are accurate literal translations, however, they were used specifically to attack doctrinal ideas that Tyndale did not agree with. The usage of terms like priest, or bishop, are not inaccurate, because those are english transliterations of the actual terms used.
If you view the priest, or bishop as an office, then it is more proper to transliterate the word because it is essentially the name of the office, or the title, and names/titles are transliterated generally.
So when Tyndale translated the names, rather than using simply using the transliterations, he was attacking the very idea of the clergy, instead displaying the offices as mere roles or functions.
Undoubtedly many today and here in specific would agree with Tyndale's opinion, however you should note that it was Tyndale's opinion, which he essentially wrote into scripture, in the place of the teaching that had been handed down for generations, since the beginning of the Church.
That is why he was declared a heretic, not because he just translated the bible.
Also, he was not put to death by the Catholic Church. The Church did condemn him as a heretic and order his arrest, but he was actually executed by Henry VIII, after Henry had already broken from the Catholic Church. The reason Henry had him executed was because Tyndale wrote a tract denouncing Henry's divorce.
