Since there is a move to make the English spelling of names in the Hebrew Bible more authentically Hebrew (Yitzak rather than Isaac), why does the EHV retain names which are so far from the Hebrew?
The EHV makes a modest step in the direction of the ongoing spelling reform which is intended to move the spelling of Hebrew names in the English Bible closer to the Hebrew spellings. An attempt is underway to move the Hebrew-based names toward a more consistent transliteration from the Hebrew. Suggested equivalents are: כ kaph=k; ק qoph=q; ח chet=ch; צ tsade=ts. But tsade is often also written as z, and chet is often written as h. Chet really needs a special character which is not an English letter—an h with a dot under it (ḥ). For example, to make a modest introduction of this reform, the EHV spells “king names,” that is, personal names ending in the word melek (which means king in Hebrew), with a final k not a final ch: Abimelek not Abimelech. But our reforms are very limited.
It would make a certain amount of academic or scholarly sense to make a consistent spelling reform, but it would not make practical sense, because we cannot ignore the fact that the EHV is an English translation, and English has established conventions for biblical names that have been used for many centuries. It would be too user-unfriendly to change names like Jacob and Isaac, which have been used for centuries, for more Hebrew-friendly names. Many of these names do not come to English directly from Hebrew but via the Greek and Latin translations.1 This applies not only to Hebrew personal names but to place names like Egypt and to the names of Persian kings. A case in point is Jerusalem, which is the established English name of the city, not the Hebrew-like Yerushalaim (which by the way seems to have been a relatively late Hebrew spelling of the name, not a genuine reflection of the early Hebrew form of the name). It is simply not feasible to take the name Jerusalem out of the English Bible. In a translation intended for general use we cannot ignore established usage in one jump. Any spelling reform must be gradual, or what seems more likely, it will never happen, just as well-meaning reforms of English spelling always falter.
If someone like the questioner wanted to use the EHV text as a basis for their own translation moving toward Hebrew spelling to create a more “Messianic” Bible, they could seek a license to do so, but at the present time we have no plans for specialized adaptations of the EHV text except for the metric Bible. Such adaptations would have their own name for their Bible like Messianic Bible based on the EHV, not EHV or Wartburg Bible.
For more information on this mess see the chapter on spelling in our book Biblical Grammar: Mechanics or Meaning?
 To cite one extreme example, the English name James has evolved from a Hebrew original Ya’aqov, via the Greek New Testament form Iakobos, via the Latin form Iacomus, to English James. Quite a journey! German churches named St. Jacobi are mostly named after NT James not OT Jacob.