That is my assessment when I consider several things.
1. My own inadequate preparation and capacity in the initial stages of my ordained ministry.
2. The ubiquitous awful Catholic preaching (which is often neither catechetical nor spiritual and at times completely perplexing or bereft of any sense at all). Take for example the consistently very poor and uninspiring preaching of the EWTN religious (without intending any personal offense to any of them or to their Order or to that incredible evangelical television and radio international network; they may be very holy, for all I know, but their preaching is far from stellar and therefore quite unfitting for such widespread transmission).
3. The centuries old Catholic tradition distinguishing between a Mass priest, a Confessor and a Preacher. Until the liturgical reform in the last century many priests did not preach at Mass. Preaching was done only on Sundays and Feast Days, often even outside of Mass (hence, when occurring in the context of the Mass, the sign of the cross before and after the Sermon and leaving the sanctuary, the maniple left on the Missal at the altar), and then typically by the Pastor of the Parish or by another designated preacher.
I should like to make the case that preaching is a priestly specialization and not just a right or capacity that comes automatically from ordination where they just throw you in however you do it, even if poorly. It seems to me that this is an area where we could heavily use those who are good at it and should forbid those who are not. We should be much more selective, and everyone would benefit. In this case less is more! In his recent Apostolic Exhortation Evangelii Gaudium Pope Francis rightly lamented the sorry state of Catholic preaching and did even exhort all priests to greater brevity, focus, and clarity. Perhaps what we need is less priests experimenting with it and reserving it to the most expert! The model that the celebrant automatically has to have something to say is at least presumptuous, an abuse and harmful to the liturgy.
I would say that as a general guideline every priest should teach basic Catechism--viz. the Penny Catechism or the Baltimore Catechism--for at least ten years before even being considered fit to enter a pulpit.
N.B. Recall that Pope Benedict's first sermon as Pope was after the Mass, (and, appropriately, in Latin). It was the first time I ever saw a priest say Mass and not preach during it but only after it (fully vested). Was not apparently uncommon before Vatican II. After having said the Extraordinary Form Mass I must say that preaching does disrupt the transcendental rhythm of the Liturgical movement and is therefore better left for the end instead of the exit and reentry of the old form. In the Ordinary Form of the Mass it does not disrupt the transcendental focus because that is already disturbed throughout (e.g. versus populo). This modern emphasis on the homily as essential to the Mass is part of the Protestantized over-emphasis on the horizontal element in the Mass to the detriment of the transcendental.
I would suggest that for starters every priest should abstain from preaching at least one ferial Mass per month, in reparation for all the bad preaching! In the Novus Ordo it might be proper, to fill the resulting liturgical gap, to leave a prolonged [e.g. 5 minute] period of silence). In the Ritus Antiquor no preaching flows quite naturally.
This entire reflection comes to me after an academic year in Rome of saying (most often public) daily and Sunday Masses, without preaching. It is actually the particular law of the diocese of Rome that priests in residence in Rome are not allowed to preach or hear confessions unless they have the Celebret of the diocese of Rome (which I did obtain and so heard confession, but still never preached for the Fraternity Parish where I was helping did not envision a daily homily, and the Pastor or the Parochial Vicar preached on Sundays).