For my professional opinion. Architecturally, would this be significant? In a way yes and in a way no. Aesthetically in a way yes, because there isn't anything like it in the area, and in a sea of low-res residential its definitely going stick out and be prominent for a number of years, but once that 58 story skyscraper goes up that point will be rather mute. Aesthetically in the world of architecture, its not really that significant. Its not doing anything radical, different, or new. So significance is only true depending on how you compare this contextually or relatively. Relatively, no. Contextually, yes. Will this building be timeless? What is timeless? Its a very ambiguous term. Again this is another, yes in some ways, and no for others. Historically, buildings that are of this scale and of this height tend last a very long time, definitely from 30 years on-wards, which in a way would make it "timeless". In the world of architecture something that is "timeless" is either something that is designed in such a simplistic way that it can both last for a long time to be reinterpreted in a number of ways, or it is something which incorporates elements that have, historically, lasted throughout time, and have often been seen as typical interpretations of "beauty" which has been proven to last. These are aspects like, proportion, symmetry / asymmetry, detailing, scale, form, how it works with light and shadow, and craftsmanship regarding its construction, and materials (often this goes all the way back to Virtruvius and what he described are the elements for a truly master work of architecture which are: Commodity, Firmness (Utility), and Delight). As for the Designer? Never heard of him, but that doesn't mean this person doesn't have any notoriety. Maybe this person has notoriety in Medical circles, or this is a friend of the owner. Could be anything. By the way, while Houston is known for not having a lot of historical architecture or buildings that have been around for a long time, we actually do. Most of the notable buildings that are in downtown were built in the 50's, 60's, and 70's which if you go all the way back to the 50's that's 70 years ago! Finally, while 700 Louisiana is great building its definitely an unfair comparison. Its basically comparing apples to oranges. They are very different buildings, and plus that building was designed by one of the greatest architects of all time, Phillip Johnson. Not exactly a fair shake.
From a personal perspective, yet is informed by my professional and educational experience, this has to be said that these responses are a matter of opinion, and thus are entirely subjective, just as anything aesthetically is. Whether something will be significant, or timeless is not really for us to say, but what others will say, and by the passage of time. Nobody can predict how long something will last. You build it and hope for the best. The artist, designer, and how I see things aesthetically, and through my informed knowledge of what is going on in architecture today, and from the past, .....no definitely not significant, and definitely not timeless. Then again who is it up for us to say or tell this owner that his opinions and feelings are wrong? Thats his opinion and he is putting up the money to make this possible. Throwing that onto him would just be a douche thing to do. I'm glad he is happy with the design and the services rendered by his architect!
There is much more that can be discussed about this, but this is already getting to long. TDLR: Its both simple and at the same time very complicated. Just depends on how you want to approach the matter.
As for you, where do you get off saying any of this? An opinion isn't a lie. A statement of fact which you know to be false, is a lie. Everything being said by the owner and developer are matters of opinion. Just because you don't like their opinion, doesn't mean they are liars. I may not like that everything gets tagged as "luxury" for instance, but that doesn't mean that they are liars. They just have a different opinion on what "luxury" is. I don't like it, but its their right to believe what they want to believe. Besides the market will dictate that anyway. This is like saying that Sales people are liars. They aren't. They tell you a story in order to get your interests to buy something. You either believe their story or you don't. Nothing that is being said by them is really objective. Only subjective.