The finest preaching I ever heard in my life was in the context of a Mennonite service. The preaching was imbued with thoroughly biblical theology - it was an example of modern day exegesis at its finest. My wife observed we would likely never hear such depth in Catholic church. I observed that the Orthodox Church would also prove wanting in this aspect.
The phenomenon of sterile is common across more sacramental forms of Christianity, that is, Christian churches where sacramentalism, as in either the mystical re-enactment of sacred events, or ritualistic and/or sometimes quasi-magical invocations of divine presence held to be of a certain efficacy by the believing body, is basis for and constant referent of worship. This is, of course, the tried and true basis of cultic observance so far as can be gleaned from recorded history. The ritual observance is conceived of as having a power in of itself and dissolving the boundaries between the sacred and the profane with such real force that it assumes pride of place in the consciousness. Liturgical action is therefore the axis upon which the religion revolves.
Sacramental Christianity is stayed, reserved, and collected to the point of restriction in its preaching. One can muse as to why. The most likely cause is the influence of Neo-Platonism on Christian theology and liturgy; the impassibility and apathea that characterizes divinity becomes the primary means of conceiving God of Scripture and leaves its mark on religious observance. We can see some shades of this in early monastic writings (where apathea becomes the central mechanism by which the ascetic life can be achieved). We can also see this in the popular asceticism to which Jerome counseled his patrons. As part of the liturgical act, preaching had to take on traits that made it qualitatively similar to the high ritualism. This is not to say one doesn't find examples that could have been to the contrary (there are homilies from Basil and Chrysostom that are potentially laden in pathos). It is to say, however, that the dominant trend was for stayed and reserved preaching. There is a culture of preaching that developed in more sacramental forms of Christianity that sees dynamic, engaged preaching (that actively gets into the "guts" of Scripture) as a distraction to the liturgical action and out of context in the liturgy.
The need for effective preaching is widely acknowledged. Towards that end, a dominant trend in sacramental churches is to pivot towards more aloof and overly academic sermons - although this approach is marred by a similar reserved quality in virtue of having been conceived and nurtured in the university, an environment that, despite whatever strengths it can reasonably claim, is characterized by a certain artificiality. Still, sacramental churches acknowledge a problem.
In truth, the problem has existed for centuries. It can be argued that it was symptomatic of the divorce between the religious establishment and the people it had a responsibility to minister to. The history of the pre-Reformation movements such as the beguines, the Waldensians (Peter Waldo), the Cathars and Albigensian, and the early mendicant orders all revolved around a common need to engage in preaching that was pointedly able to direct itself into the lives and concerns of its audience. The medieval age was complemented by a dominant cultural belief in the activity of the supernatural in daily life - we cannot discount how important this was to the success of religious movements that, in one way or another, highlighted preaching, which was oftentimes in conjunction with what we would today classify as either charismatic experience, or perhaps even gnosis. Waldo, for instance, is alleged to have received inspiration for a radical life of alleviating poverty and rejecting Roman excess after hearing a sermon preached on the life of St. Alexius. He is an exemplar of an exciting time in the history of Western Christianity, when the ambient presence of the age of faith led to experiences at odds with the religious establishment.
History shows how these movements all eventually headed. Ecclesiastical authority sought (for a variety of reasons) conformity, regulation, and suppression where deemed necessary. Even movements more aligned with ecclesiastical authority, such as the Dominicans, had prescriptions governing their preaching, down such details as cadence, physical motions, etc. Groups that found assimilation (such as the Dominicans and Franciscans) or those that found tolerance (such as certain beguines), found the preaching content and charismatic experience of their movements strictly regulated, to the point that one can argue the final product that received ecclesiastical approval was on tangentially related to the original phenomenon. Certainly, the experience of the supernatural and subsequent proclamation were suppressed in favor of a model complementary towards the hierarchy., the consequences of which would emerge with the likes of Luther, Calvin, et al.
It is tempting to believe that the problem with preaching in sacramental churches ultimately derives from the alleged experience of the divine that surrounds it. Whether or not any religious experience happened (and mind you, it is worth noting that this caveat applies to sacramental experience as well) is beyond the means of verification of most human agencies, ecclesiastical or otherwise. If an experience of the supernatural did in fact occur, the role of the hierarchy is challenged - pretenses to mediating the access to God become less certain and positions of authority based upon said pretenses are challenged if other people begin to believe in the authenticity and authority of the experience. Reserved and restricted preaching has its virtue in that it does not risk any disruption to the religious system built up around the sacramental/liturgical experience. Preaching that otherwise defies liturgical reserve risks offers an experience of the supernatural that is not contained in the liturgical act or sacraments and thus falls outside of the regulation of a given religious establishment. This was acutely observable in the medieval period until the Reformation, wherein the religious authority that mediated the sacramental access to the divine found its unique legitimacy threatened by various movements that fell outside of its normal channels.
Rightly or wrongly, the course of history has dictated that preaching in any appreciable sense is a religious phenomenon reserved to branches of Christianity characterized by a low sacramentalism and divergence from traditional lines of apostolic succession. At root of this divergence is the experiential encounter with God producing two distinct and at times mutually exclusive notions as to how divine presence is effected by human participants.