No, it's not presumptuous of the Cardinal at all. Note what was said by the Cardinal from the article: "...regardless a comprehensive study was completed in 2002."
You can look at that very comprehensive study here.
"Little new" is an appropriate response when asked what will come from such a study. The 2002 study was pretty exhaustive, and for those thinking that it will be discovered that there were female deacons in the Church at one point will be disappointed. That's why "little new" can be said will come from this; because it's a known fact that there were never female deacons in the Church. There were deaconesses at one point for sure, but they belonged to the minor orders. Minor orders today include lectors and acolytes. Those in the minor orders are not ordained via the Sacrament of Holy Orders. The major orders, those which are conferred using the Sacrament of Holy Orders, are deacon, priest, and bishop.
From the 2002 study linked above, emphasis mine:
"Deaconesses should carry out the anointing of women in the rite of baptism, instruct women neophytes, and visit the women faithful, especially the sick, in their homes. They were forbidden to confer baptism themselves, or to play a part in the Eucharistic offering (DA 3, 12, 1-4)...
"The Constitutiones Apostolorum which appeared in Syria towards 380... insist[s] that the deaconesses should have no liturgical function (3, 9, 1-2), but should devote themselves to their function in the community which was "service to the women" (CA 3, 16, 1) and as intermediaries between women and the bishop. It is still stated that they represent the Holy Spirit, but they "do nothing without the deacon" (CA 2, 26, 6). They should stand at the women's entrances in the assemblies (2, 57, 10). Their functions are summed up as follows: "The deaconess does not bless, and she does not fulfill any of the things that priests and deacons do, but she looks after the doors and attends the priests during the baptism of women, for the sake of decency" (CA 8, 28, 6)...
"Even in the fourth century the way of life of deaconesses was very similar to that of nuns. At that time the woman in charge of a monastic community of women was called a deaconess, as is testified by Gregory of Nyssa among others. Ordained abbesses of the monasteries of women, the deaconesses wore the maforion, or veil of perfection. Until the sixth century they still attended women in the baptismal pool and for the anointing. Although they did not serve at the altar, they could distribute communion to sick women. When the practice of anointing the whole body at baptism was abandoned, deaconesses were simply consecrated virgins who had taken the vow of chastity...
In conclusion, "With regard to the ordination of women to the diaconate, it should be noted that... The deaconesses mentioned in the tradition of the ancient Church - as evidenced by the rite of institution and the functions they exercised - were NOT purely and simply equivalent to the deacons."
Once we understand that the Cardinal is only affirming that we won't suddenly discover that female deacons (as opposed to deaconesses) were around in the early Church, we see that his comments are not presumptuous or negative in the least.