Yes, I know this. I don't mean to be rude but I've basically already stated this twice...
Hm, what were you looking for with "The only question I really have is if he would be much higher than Lucca or not, because while his magic stat is higher than hers, she still has a pretty beast Magic development to begin with. Hers is the second highest in the game."? I seem to have missed the intent of the query.
(Sorry, repeating numbers is a habit of mine, I'm used to having to bring up a number several times before it sinks in.)

That's a really black & white notion of how the conversation could go. Seriously, there's so much more that could have been done with that and beyond. I find his rather dull and uninteresting dialogue to be the result of weak writing and/or laziness. However I'm told that Magus' character actually is shown to have more attachment to his mother in the Japanese version and that more interesting dialogue ensued, but of course we don't get to see that.
Looks like the conversations are more similar than you were led to believe.
NA Dialog:
MAGUS: Idiots...
Nothing can live forever.
MAGUS: Zeal...
A pitiful woman, duped by Lavos!
MAGUS: I, myself, will bring an end
to all of this!

JP Dialog:
MAGUS: Foolish......
All existence is unable to escape from the fate
of perishing......
MAGUS: Zeal.
A sad woman enthralled by Lavos.
Pitiful at best......
MAGUS: I will bring it all to an end by my hand!

Just curious, what do you feel it would have been appropriate for him to add?

Granted it's an overused cliche, but it's not recycled anymore than Magus-like characters.
Very true, but characters like this kind of feel like a personal attack on me. Cliche's don't bother me as much, since I don't consume very much media. (I usually don't have much free time.)

Still, feelings of love and affection can open new doors and change some people.
I agree completely, and there are stories on the subject I enjoy very much. It is the concept that it is an expected outcome that vexes me. And most of the time the change seems very unbelievable.

Well he's just as expected, uninteresting and poorly-written as any other Magus-type character in these JRPG/anime genres, except he strangely has less development than Magus despite the fact that SO4 is a modern game [go figure on that one]. I imagine that a legion of fanboys are lining up to boast Arumat's "badassness" as we speak or have already done so just because he has [wait for it!] long, white hair, acts cold, talks down to others, and hey, even wields a scythe! Oh, and he's also riven by inner tragedy with a depressing past and vows to avenge it in some manner. Can't forget that one. That one will "surely" make him more of an interesting character. I guarantee that this character is the primary factor that made any money for Tri-Ace through SO4.
Sounds like I'll love him