This proposal is inspired by the Revised Romanisation of Korean, and the new romanisations of some Slavic languages.

This revised romanisation aims:

1. To maintain a simple, consistent orthography
2. To better appeal to non-Dovahzul speakers
3. To relegate one Dovahzul character to one Latin character each, where possible

• The vowel ah is romanised as â. 
• The long vowels aa ii oo uu are romanised as á í ó ú.
  (NOTE: Acute accents are used because this site does not render macrons.)
• The vowels ei ey ir ur are not affected by this romanisation, as their sounds cannot be easily compressed into a single letter.
• In the event that vowels run together, they are separated with an apostrophe ('). (Nahagliiv - Nâ'aglív).
  The vowel combinations ae and au are an exemption. In particular, ae is meant to represent the /æ/ sound and theoretically should have a Dovahzul character relegated to it.
• The new romanisation system will ignore the double-letter rule for plural words (dovâhe for dovahhe). Instead, a new rule will be formed that the letter h will always go after â. 
• Compound words using the preposition se will be separated by dashes. (Ahrolsedovah - Ârol-se-Dovâ). 

Under this new romanisation, Dovahzul is rendered Dovâzul and Thuum is rendered Thúm. 
Here is the first verse of the Song of the Dragonborn, rendered to demonstrate:

Dovâkín, Dovâkín, nál ok zin los vârín,

Wâ dein vokul mâfaerák âst vál

Ârk fin norok pál grán fod nust hon zindro zán

Dovâkín, fâ hin kogán mu drál 

There's a mild difiiculty here, which I have encountered with the Dovahzul font file I use that approaches those extra runes in a similar manner:

The means of typing those accents isn't common knowledge. As such, it would work fairly well for handwritten text, but arguably makes it *less* accessible in a digital medium.

SethVeeper

There's a mild difiiculty here, which I have encountered with the Dovahzul font file I use that approaches those extra runes in a similar manner:

The means of typing those accents isn't common knowledge. As such, it would work fairly well for handwritten text, but arguably makes it *less* accessible in a digital medium.

I could argue that you also cannot easily type diacritics in tonal languages like Vietnamese, which relegates up to 3 diacritics to one letter. I could also say how Russian romanisations have evolved to using š in place of sh, or x/h in place of kh. In fact, this reasoning is why I thought up an idea of a revised romanisation of Dovahzul.