Note that i actually do not endorse this.
For the most part i believe that switching to pinyin would not have any detrimental consequences. My reasoning for this is:
(A) for a long time many people in china were illiterate and did not have trouble communicating without resorting to characters.
(B) today in general speech people can have conversations without needing to resort to writing.
(C) i have converted many wikipedia articles to pinyin and asked native speakers to read them. The consensus is that doing so is slow, but the content is understandable.
We can argue against (a) by pointing out that many earlier dialects had more tones and a large phonetic inventory than modern mandarin. I am not qualified to give real judgements on this as i have little knowledge of how the frantic reforms of the twentieth century in particular went.
We can argue against (b) by pointing out that it is common to resort to characters in day to day life in order to disambiguate. The phrase 木子李 would either have no meaning, or become a more obscure old saying. In fact perhaps it wouldn't be needed at all. However, harbin's two lijiang streets, 莅江路 and 丽江路, would still need to be disambiguated and using meili de li no longer has any context.
We can argue against (c) by finding different content that is harder to understand. A classic example that is often referenced in this discussion is shī shì shí shī shǐ, the lion-eating poet in the stone den poem. I think this is a poor example, firstly because it is written in classical chinese and not mandarin with the deliberate goal of showing that romanisation systems designed for mandarin will face significant issues when they are used for classical chinese, and second because people generally don't speak like that.
It is cruel to get rid of an entire category of creativity from a language, but i think doing so does not actually make a strong argument against changing the writing system.
More significant issues arise in more technical fields. I know that tin and selenium are both xī. That probably affects most people very little. I know i only have ever used the word selenium in discussions about learning the periodic table for fun. But it will affect some people in the domains where it matters.
I'm not alone in thinking that pinyin is the better system to use to teach beginner chinese learners. This is mostly because focusing on one area of comprehension at a time is a way better idea that making someone waste all their time up front learning a whole new way to write. But i also am not, at least in the twentieth century, alone in thinking that pinyin could theoretically be used instead of hanzi.
Would it severely damage the culture and art? Almost certainly, and for that reason i don't actually endorse the idea. But that shouldn't stop us imagining.
An interesting related article
Now another note: i was shown that 花 is flower, 生 is birth, and 花生 is peanut. But in pinyin, hua is flower, sheng is birth, and huasheng is peanut. I think this one seems much less unintuitive (forgive the double negative)? In english stud means nail, dent means hole, but student means a person who is learning. This doesn't trip people up, because we just see it as a different word. Frequently the characters in compound words make sense in chinese, but other times they seem dubious (牦牛 is one i've talked about before).