Criticism:
“Textually, Erasmus omitted “God” in Revelation 1:8. TR editions didn’t catch this omission until the mid 1800’s, and so the KJV likewise omits “God” from the text. Despite the fact that no Greek manuscripts of the passage (except for two as I recall) which contain this passage have omitted this word. It is a clear textual mistake in the TR and KJV, whose history is easy to trace.”

Modern version proponents like to point out that the critical text adds the word “God” in Rev. 1:8. But consider the whole picture: Verse 8 in the critical text omits “the beginning and the ending.” Verse 9 omits “Christ” two times. Verse 11 omits “I am Alpha and Omega, the first and the last.” The overall effect of the modern version rendering of Revelation chapter one is to weaken its testimony to Christ‘s deity as compared with the Greek Received Text and faithful translations such as the King James Bible.

There are several words omitted from both Revelation 1:8 and 1:11 which provide strong testimony to the fact that the Lord Jesus Christ is Himself Jehovah, the Lord God Almighty.

The Received Text identifies Christ, the speaker in 1:8, 11, as the Almighty, the Alpha and the Omega, the beginning and the ending, the first and the last. The critical text, by adding the word “God” in v. 8 and omitting the phrases highlighted above in v. 8 and v. 11, change the speaker in v. 8 from Christ to the Father, and remove the testimony to Christ’s Deity from this passage.

There is excellent Greek MSS support for the Received Text reading (which is also receives support from other sources; e. g., in v. 8, the Old Latin, the Vulgate, and other witnesses).
While the textual situation in the book of Revelation is complicated, the Received Text tends to follow the largest single group of MSS. “Hoskier declared, concerning the TR text of Revelation: “I may state that if Erasmus had striven to found a text on the largest number of existing MSS [manuscripts] in the world of one type, he could not have succeeded better. . . . Here then is a powerful example of God’s guiding providence in preserving the text of Revelation.”

Revelation 20:12
And I saw the dead, small and great, stand before God; and the books were opened: and another book was opened, which is the book of life: and the dead were judged out of those things which were written in the books, according to their works.
(KJV)

kai« ei•don tou\ß nekrou/ß, mikrou\ß kai« mega¿louß, e˚stw◊taß e˙nw¿pion touv Qeouv, kai« bibli÷a hjnewˆ¿cqhsan: kai« bibli÷on a‡llo hjnewˆ¿cqh, o¢ e˙sti thvß zwhvß: kai« e˙kri÷qhsan oi˚ nekroi« e˙k tw◊n gegramme÷nwn e˙n toi√ß biblioiß, kata» ta» e¶rga aujtw◊n.
(TR)

And I saw the dead, great and small, standing before the throne, and books were opened. Then another book was opened, which is rthe book of life. And the dead were judged by what was written in the books, according to what they had done.
(ESV)

kai« ei•don tou\ß nekrou/ß, tou\ß mega¿louß kai« tou\ß mikrou/ß, e˚stw◊taß e˙nw¿pion touv qro/nou. kai« bibli÷a hjnoi÷cqhsan, kai« a‡llo bibli÷on hjnoi÷cqh, o¢ e˙stin thvß zwhvß, kai« e˙kri÷qhsan oi˚ nekroi« e˙k tw◊n gegramme÷nwn e˙n toi√ß bibli÷oiß kata» ta» e¶rga aujtw◊n.
(CT)

Since Jesus Christ is the One sitting on this throne, the Received Text declares that He is “God,” while the critical text changes “God” to “throne.” Concerning the MSS evidence in the book of Revelation, see the comments on Revelation 1:8, 11 above.

We can clearly see there is a theological error in the Critical Text. The Received Text has manuscript and witness support, thereby eliminating any supposed 'errors'.