The Socinians thought so, and their approach to it is relevant to understanding some contemporary improvements on orthodoxy. In his discussion of Socinianism William Cunningham noted that:
Socinianism,--and indeed, this may be said of most other systems of false religion,--represents God as a Being whose moral character is composed exclusively of goodness and mercy; of a mere desire to promote the happiness of his creatures, and a perfect readiness at once to forgive and to bless all who have transgressed against him. They thus virtually exclude from the divine character that immaculate holiness which is represented in Scripture as leading God to hate sin.Historical Theology Volume 2, p. 172
Cunningham points out that this dispute over God's being and attributes has a direct bearing on how the atonement is understood since it touches on the issue of the necessary or voluntary punishment of sin. Either God punishes sin because of his holy nature or else he punishes it, or overlooks it, as a mere act of his will. Of course if he doesn't need to punish it then he can freely forgive it merely by speaking a word. But if sin must be punished then he will freely forgive it only at great cost to himself in the penal substitutionary death of his Son.
It is interesting to note that Cunningham's description of the Socinian recasting of God's attributes is seen in some contemporary authors:
love is the most important quality we attribute to God.Richard Rice in The Openness of God, p. 15
The tragedy is that over the centuries the Church has time and again failed to communicate, even to understand, this greatest and deepest of all truths. Perhaps some of the most disastrous examples of this are, paradoxically, the Church's historic creeds...the fact that the God of the universe is the God who claims, not only that he loves, but also that he chooses to define himself as love has become one of the world's best kept secrets.
People still believe that the Christian God is a God of power, law, judgement, hell-fire and damnation. A God whose strapline is probably, "Get in line fast or I'll squash you!"Steve Chalke and Alan Mann, The Lost Message of Jesus, P. 55-6, 63
The Bible never defines God as anger, power or judgement--in fact it never defines him as anything other than love.
William Cunningham has a striking observation about the doctrine of God, Socinian or orthodox, and the implications of this for other doctrines:
It is true of all systems of theology,--taking that word in its wide and common sense, as implying a knowledge of all matters bearing upon our relation to God and our eternal destinies,--that they are materially influenced, in their general character and complexion, by the views which they embody about the divine attributes, character, and government,--that is, about theology in the restricted meaning of the word, or the doctrine concerning God.Historical Theology Vol 2, p. 171-2
Hence we find that, in many systems of theology, there are introduced, under the head "De Deo," and in the exposition of the divine attributes, discussions more or less complete, of many topics that are afterwards taken up and illustrated more fully under their own proper heads,--such as providence, predestination, and grace.
Conclusion: It is possible to remove all necessity for a penal substitutiony atonement because of decisions made when dealing with the doctrine of God, particularly his being and attributes. Although the doctrine of atonement should be arrived at and established exegetically, presumptions that militate against it can be factored in ever before the exegesis proper begins.