Is it helpful from a Buddhist perspective to always avoid such pronouns?
To avoid those pronouns reminds me of what Ursula Le Guin in this speech called "the father tongue".
As described in the first few paragraphs of Ursula's speech, avoiding "I" might often be good practice (because "I" is usually not the "subject").
Note: Le Guin is a novelist; she has written among other things a translation of the Tao Te Ching, and she is I think humane, and writes well; but she is not a formally-Buddhist teacher (and neither am I) so this is not a formally-Buddhist answer. I give this as a personal opinion instead of quoting canon because I don't know that there is a canonical answer: Buddhists do not in my experience avoid saying "I".
I deliberately wrote "me" into the first sentence, to signal that was a personal not a canonical answer. It might have been easy to try to make it sound more authoritative: "Avoiding those pronouns is what Le Guin called etc."
But it wouldn't actually be more authoritative though, even if it were trying to sound that way.
I try to write truthfully at least: i.e. "Right Speech" (although Right Speech is more difficult than simply being truthful; it would also have to be appropriately-timed and helpful and welcome).
Sometimes we talk about things ("that table's dirty"), sometimes opinions ("I think that table looks dirty").
I usually try to avoid using pronouns in these context but sometimes the ease of using them overcomes my efforts, like with this sentence.
Yes, well that's what happens when you write about yourself. :-)
Is using it just a symptom and the underlying disease needs to be treated?
I doubt it's helpful to always avoid such pronouns.
It makes sense to use it sometimes: e.g. when you go to a doctor to say, "I am sick" rather than "This person (points finger) is sick."
If you're not a monk it might be basic politeness too, when shopping: "Good morning. I would like a loaf of bread, please."
There are plenty of uses of the word "I", e.g. on pages like the following: http://www.accesstoinsight.org/ptf/dhamma/sacca/sacca4/samma-ditthi/kamma.html
These Zen stories are full of the word "I": http://www.ashidakim.com/zenkoans/zenindex.html
Buddhists are at least supposed to be tolerant of each other, I don't see why you should have to avoid "I".
I think a more usual way to formulate your question is how to view "self". For example, seeing "self" as eternal is wrong, but seeing "self" as destructible is wrong. And that answer is more difficult. But I'm pretty sure that the "Middle Way" is part of the answer to that question.